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Search for "kinetic" in Full Text gives 622 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin
- Jon Lundstrøm,
- Emilie Gillon,
- Valérie Chazalet,
- Nicole Kerekes,
- Antonio Di Maio,
- Ten Feizi,
- Yan Liu,
- Annabelle Varrot and
- Daniel Bojar
Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31
- . An immobilization level of 900 response units (RU) was obtained. A reference surface was always present in flow cell 1, allowing for the subtraction of bulk effects and non-specific interactions with streptavidin. The mammalian-produced CMA1 was injected in single cycle kinetic over the flow cell
- experiments, nine concentrations of LacNAc (Elicityl, #GLY008) from 10 to 0 mM with a dilution coefficient of two supplemented with a fixed concentration of 0.8 µM was injected into the cell surface in multiple cycle kinetic with an association time of 500 s and a dissociation time of 12 s at a flow rate of
Graphical Abstract
Figure 1: Characterizing a new lectin from the melon Cucumis melo. (a) Evolutionary relationships of common R...
Figure 2: Characterizing the binding specificity of CMA1. (a, b) Lectin produced in mammalian cells was analy...
Figure 3: Assessing and quantifying in-solution binding of CMA1. (a) Erythrocyte agglutination assay. Using r...
Figure 4: Structural insights into the binding mechanism of CMA1. (a, b) Overall representation of the N-term...
Photochromic derivatives of indigo: historical overview of development, challenges and applications
- Gökhan Kaplan,
- Zeynel Seferoğlu and
- Daria V. Berdnikova
Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23
- photochromic N,N'-diacyl derivatives of indigo, first examples of photochromic indigos containing aromatic N,N'-substituents 1984: first report on intra- and intermolecularly bridged photochromic N,N'-substituted indigos (follow-up studies in 1989, 2021) 1985: detailed kinetic studies of the thermal backward Z
- the lack of steric restriction [57]. The thermal Z–E isomerization of N,N'-diacylindigos was further investigated by Sueishi and co-workers in 1985 [58]. In this study, the kinetic experiments for a range of derivatives 9a, 9c, 9d, 9g, 9i–m bearing various N,N'-diacyl substituents in different
Graphical Abstract
Figure 1: Precursors used in the synthesis of indigo [4].
Figure 2: a) Intramolecular (a = 2.26 Å) and intermolecular (b = 2.11 Å) hydrogen bonds in indigo, b) crystal...
Figure 3: Bond length in the indigo molecule obtained from the single crystal X-ray analysis [12], the typical bo...
Figure 4: The structure of the indigo chromophore (H-chromophore, highlighted in blue), asterisk indicates th...
Figure 5: Influence of substituents in the benzene rings on the color of indigo derivatives.
Figure 6: a) E–Z photoisomerization of indigo and b) photoinduced proton transfer in the excited state, aster...
Figure 7: Structures of indigo derivatives discussed in this review.
Figure 8: Photoswitching of N,N'-diacetylindigo (9a) in CCl4 (c = 17.1 µM; cell length = 5.0 cm) irradiated w...
Figure 9: Photoisomerization of compound 18c upon irradiation with red light and schematic representation of ...
Figure 10: Schematic representation of indigo-type (left) and amide-type (right) resonances in N,N'-acetylindi...
Figure 11: Suggested intermediates for the double bond cleavage for the thermal relaxation of N,N'-diacylindig...
Figure 12: Zwitterionic resonance structures of Z-indigo.
Figure 13: Photos of crystalline N,N'-di(Boc)indigo 17a its solutions in 1) DMSO, 2) DMF, 3) N-methyl-2-pyrrol...
Figure 14: Structural isomers of indigo.
Figure 15: Photochromism of indirubin derivatives and supramolecular complexation of the E-isomers with Schrei...
Figure 16: Photoisomerization of the protonated isoindigo.
Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles
- Yumei Wang,
- Guangzhu Wang,
- Yanping Zhu and
- Kaiwu Dong
Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20
- great attention in organic synthesis. Various methods [9], including reductive hydrogenation [10][11], kinetic resolution [12][13][14], functionalization of indole [15], and de novo construction of chiral 2-substituted indolines, have been developed [16][17][18][19][20]. In recent years, the metal
Graphical Abstract
Figure 1: Structures of bioactive fluorinated indole derivatives.
Scheme 1: Synthesis of chiral indolines via asymmetric reduction.
Scheme 2: Substrate scope of 3,3-difluoro-3H-indoles.
Scheme 3: Experiment at 2 mmol scale.
Figure 2: Proposed mechanism for the transfer hydrogenation reaction.
Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs
- Amina Moutayakine and
- Anthony J. Burke
Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19
- File 6: Experimental procedures and spectral data (NMR, mass spectra) and key kinetic studies. Funding This work received financial support from the Fundação para a Ciência e Tecnologia (FCT Portugal) through the project UIDB/50006/2020 | UIDP/50006/2020.
Graphical Abstract
Figure 1: Biologically active dibenzodiazepinones.
Scheme 1: Different synthetic routes to DBDAPs (a–c), including our novel approach (d).
Scheme 2: One-pot synthesis of 5H-dibenzo[b,e][1,4]diazepin-11-ol (5).
Scheme 3: Scope of the Chan–Lam coupling between o-phenylenediamines and 2-bromophenylboronic acids (please n...
Scheme 4: Scope of the synthesis of DBDAPs. Please note that product 4g contained some unidentified impuritie...
Scheme 5: Proposed mechanism.
Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes
- Michio Yamada
Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13
- positioning of the [2 + 2] CA or RE step as the rate-determining step may depend upon the structural attributes of the electrophiles and nucleophiles. In 2023, Nielsen et al. conducted an exhaustive kinetic analysis of the [2 + 2] CA–RE reaction involving 4-trimethylsilylethynylaniline and TCNE by leveraging
- between AB and P, from which C1 is generated. Notably, this additional route significantly accelerates the overall reaction. The researchers reported that the conversion of the ABP complex into C1 transpired at a markedly accelerated rate compared with the conversion of AB alone, with a kinetic constant
- 100 °C to generate 30c. Conversely, the transformation of 28b proceeded at 45 °C, and the smallest macrocycle 28a reacted with TCNE at 0 °C. Kinetic investigations revealed that the rate-determining step in the reaction involving 28a–c with TCNE was the second-order [2 + 2] CA step, succeeded by the
Graphical Abstract
Scheme 1: Pathway of the [2 + 2] CA–RE reaction of an electron-rich alkyne with TCNE or TCNQ. EDG = electron-...
Scheme 2: Reaction pathway for DMA-appended acetylene and TCNEO.
Scheme 3: Pathway of the [2 + 2] CA–RE reaction between 1 and DCFs.
Scheme 4: Sequential double [2 + 2] CA–RE reactions between 1 and TCNE.
Scheme 5: Divergent chemical transformation pathways of TCBD 6.
Scheme 6: Synthesis of 12.
Scheme 7: [2 + 2] CA–RE reaction of 1 with 14. TCE = 1,1,2,2-tetrachloroethane.
Scheme 8: Autocatalytic model proposed by Nielsen et al.
Scheme 9: Synthesis of anthracene-embedded TCBD compound 19.
Scheme 10: Sequence of the [2 + 2] CA–RE reaction between dibenzo-fused cyclooctyne or cyclooctadiyne and TCNE...
Scheme 11: [2 + 2] CA–RE reaction between the CPP derivatives and TCNE. THF = tetrahydrofuran.
Scheme 12: [2 + 2] CA–RE reaction between ethynylfullerenes 31 and TCNE and subsequent thermal rearrangement.
Scheme 13: Pathway of the [2 + 2] CA–RE reaction between TCNE and 34, followed by additional skeletal transfor...
Scheme 14: Synthesis scheme for heterocycle 38 from the reaction between TCNE and 1 in water and a surfactant.
Scheme 15: Synthesis scheme of the CDA product 41.
Scheme 16: Synthesis of rotaxanes 44 and 46 via the [2 + 2] CA–RE reaction.
Scheme 17: Synthesis of a CuI bisphenanthroline-based rotaxane 50.
Figure 1: Structures of the chiral push–pull chromophores 51–56.
Figure 2: Structures of the axially chiral TCBD 57 and DCNQ 58 bearing a C60 core.
Figure 3: Structures of the axially chiral SubPc–TCBD–aniline conjugates 59 and 60 and the subporphyrin–TCBD–...
Figure 4: Structures of 63 and the TCBD 64.
Figure 5: Structures of the fluorophore-containing TCBDs 65–67.
Figure 6: Structures of the fluorophore-containing TCBDs 68–72.
Figure 7: Structures of the urea-containing TCBDs 73–75.
Figure 8: Structures of the fullerene–TCBD and DCNQ conjugates 76–79 and their reference compounds 80–83.
Figure 9: Structures of the ZnPc–TCBD–aniline conjugates 84 and 85.
Figure 10: Structures of the ZnP–PCBD and TCBD conjugates 86–88.
Figure 11: Structures of the porphyrin-based donor–acceptor conjugates (89–104).
Figure 12: Structures of the porphyrin–PTZ or DMA conjugates 105–112.
Figure 13: Structures of the BODIPY–Acceptor–TPA or PTZ conjugates 113–116.
Figure 14: Structures of the corrole–TCBD conjugates 117 and 118.
Figure 15: Structure of the dendritic TCBD 119.
Figure 16: Structures of the TCBDs 120–126.
Figure 17: Structures of the precursor 127 and TCBDs 128–130.
Figure 18: Structures of 131–134 utilized for BHJ OSCs.
Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations
- Laura Abella,
- Gerard Novell-Leruth,
- Josep M. Ricart,
- Josep M. Poblet and
- Antonio Rodríguez-Fortea
Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10
- nanotubular-shaped fullerene inside the peapod. Kinetic analysis with the variable-temperature (VT) SMART-TEM method for the aforementioned C60 dimerization has also been reported by these authors [9]. They concluded that the SWCNT, which accumulates energy by the interaction with the electron beam, activates
- of dimer 1-Cs•+ (see Supporting Information File 1, Figure S9). However, TS-2 is significantly lower in energy. Therefore, in gas phase, dimer 1-D2h•+ is predicted to be the thermodynamic and the kinetic product. Once our methodology was validated, the energy profile for the formation of dimer 1-Cs
- pseudopotentials [16] while valence electron density was expanded in plane waves with a maximum kinetic energy of 400 eV. The model of SWCNT was 29.61 Å long and with a diameter of 13.65 Å, embedded in a box of 30 × 30 Å of vacuum in the plane perpendicular to the nanotube axis. The gas-phase structures were in a
Graphical Abstract
Scheme 1: Proposed radical cation mechanism for the dimerization of two C60 cages inside a metallic carbon na...
Figure 1: DFT-optimized structures of C60 dimers 1-D2h, 1-Cs and nanotubular C120-NT-D5d fullerene.
Figure 2: Energy profiles for the dimerization of 2 C60 and C60 + C60•+ fullerenes in the gas phase. All ener...
Figure 3: Energy profiles for the dimerization of 2 C60 (neutral) and C60 + C60•+ (radical cation) fullerenes...
Figure 4: Proposed sequence of C60 dimers up to the formation of dimer HPR-Cs•+.
Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor
- Pengcheng Li,
- Daniel Kowalczyk,
- Johannes Liessem,
- Mohamed M. Elnagar,
- Dariusz Mitoraj,
- Radim Beranek and
- Dirk Ziegenbalg
Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9
- (regime 1), the hydrogen generation rate is typically limited by the available photon flux and can be approximated first order with respect to light intensity. For higher photon fluxes, kinetic limitations appear (second regime) since the larger amount of charge carriers present in the photocatalysts
- and reaction rate [42], which was used in this work to fit the experiment results (see Equation 4). where is the average (observed) reaction rate, k* is the kinetic rate constant, θ is the surface coverage of the photocatalyst, α is the optical density, ϕ is the quantum yield, qp is the volumetric
Graphical Abstract
Scheme 1: Photocatalytic hydrogen evolution with Pt-loaded polymeric carbon nitride.
Figure 1: SEM images of the Pt-PCN photocatalyst at different magnifications.
Figure 2: SEM-EDX elemental mapping images of C, N, and Pt on a particle.
Figure 3: Exemplary results of the mixing experiments using methylene blue to visualize and quantify fluid fl...
Figure 4: Red channel values of ROIs with different stirring speeds: (a) left space between reactor and draft...
Figure 5: Quantified mixing time using different stirring speeds.
Figure 6: Chemical actinometry results: (a) actinometer conversion at different irradiation time, (b) photon ...
Figure 7: Photon flux in the loop reactor with respect to the LED electrical current.
Figure 8: Absorbance as function of photocatalyst loading for different optical path lengths.
Figure 9: Long-term operation of the loop photoreactor.
Figure 10: Visualization of the response surfaces of the modified DOE model for the four parameters: (a) photo...
Figure 11: Parity plot of the measured photocatalytic hydrogen generation rate versus the values predicted by ...
Figure 12: Effect of photon flux on hydrogen generation rate: (a) hydrogen generation rate as function of the ...
Figure 13: Effect of inert gas flow rate on hydrogen generation rate: (a) hydrogen generation rate as a functi...
Figure 14: Effect of photocatalyst loading on the hydrogen generation rate: (a) hydrogen generation rate as fu...
Figure 15: Effect of stirring speed on hydrogen generation rate: (a) hydrogen generation rate as function of i...
Figure 16: 3D plot of AQE for different studied parameters: (a) AQE for different photon fluxes and inert gas ...
Figure 17: Reactor design: (a) CAD drawing of the loop reactor, (b) picture of the manufactured loop reactor.
Figure 18: Assembled reactor and 3D printed parts: (a) the whole reactor setup, (b) 3D printed propellers.
Figure 19: Photocatalytic reaction setup: (a) reaction setup flow diagram, (b) reaction setup in lab. 1 argon ...
Using the phospha-Michael reaction for making phosphonium phenolate zwitterions
- Matthias R. Steiner,
- Max Schmallegger,
- Larissa Donner,
- Johann A. Hlina,
- Christoph Marschner,
- Judith Baumgartner and
- Christian Slugovc
Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6
- with several Michael acceptors [34]. In this work we present the formation of stable zwitterions from the reaction of 2,4-di-tert-butyl-6-(diphenylphosphino)phenol (1) and a variety of different Michael acceptors and disclose kinetic investigations on the zwitterion formation with carbonyl and non
- donors attached to the alkyl substituent of the phosphonium center (Figure 3). This hypothesis is further supported by the observation of two very different chemical shifts for the two amide protons in the 1H NMR spectrum of 2b in CDCl3 giving resonance at 5.21 and 8.58 ppm. Kinetic studies In the next
- . The strong Michael acceptors were methyl acrylate (E = −18.84) bearing a carbonyl-based electron-withdrawing group and acrylonitrile (E = −19.05) featuring a geometrically different electron-withdrawing group. Acrylamide was selected as a weak (E = −21.8), carbonyl-based Michael acceptor. The kinetic
Graphical Abstract
Scheme 1: Reaction of 1 with various Michael acceptors (EWG = electron-withdrawing group) forming the zwitter...
Figure 1: 1H NMR spectrum of 2a recorded on a 300 MHz spectrometer in CDCl3 at 23 °C; the inset shows a 3D-mo...
Figure 2: a) Molecular structure of 2a, hydrogen atoms omitted for clarity, thermal ellipsoids drawn at 30% p...
Figure 3: Left: UV–vis spectra of 2a, 2b and 2d in chloroform (straight lines) and in methanol (dotted lines)...
Figure 4: Conversion of 1 (initial c = 0.25 mM) toward 2a, 2b, or 2d in the presence of the respective Michae...
Scheme 2: Proposed mechanism for intramolecular proton transfer in zwitterion formation with Michael acceptor...
NMRium: Teaching nuclear magnetic resonance spectra interpretation in an online platform
- Luc Patiny,
- Hamed Musallam,
- Alejandro Bolaños,
- Michaël Zasso,
- Julien Wist,
- Metin Karayilan,
- Eva Ziegler,
- Johannes C. Liermann and
- Nils E. Schlörer
Beilstein J. Org. Chem. 2024, 20, 25–31, doi:10.3762/bjoc.20.4
- a reaction substrate and product or analysis of kinetic studies that include several data points) or overlaying of 2D spectra, for example, to show the different outcomes of related experiments such as COSY/TOCSY or HSQC/HMBC. Students will be enabled to learn these online comparison aspects by
Graphical Abstract
Figure 1: NMRium.org user interface showing a 2D NMR quiz for an unknown compound with a given molecular form...
Figure 2: NMRium interface assignment functionality for a drag-and-drop example.
Figure 3: Analysis of overlapping signals with the NMRium ranges editor.
Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway
- Seiji Kawai,
- Akito Yamada,
- Yohei Katsuyama and
- Yasuo Ohnishi
Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1
- reaction enabled us to perform a kinetic analysis of AvaA7, which confirmed that AvaA7 catalyzes the denitrification of 3-diazoavenalumic acid in avenalumic acid biosynthesis. This study deepened our understanding of the highly reducing type II polyketide synthase system as well as the diazotization
- of 3-aminocoumaric acid (3-ACA, 3) and 3-AAA (7) with considerably higher efficiency than AvaA6 in avenalumic acid biosynthesis. We also performed kinetic analysis of AvaA7, which catalyzes the denitrification of 3-DAA (8) in avenalumic acid biosynthesis, using the highly efficient diazotase CmaA6
- diazotization catalyzed by CmaA6 was much higher than that of AvaA6; almost 100% of 3-ACA and 3-AAA were converted to corresponding aromatic diazo compounds 4 and 8, respectively (Figure 3C). Kinetic analysis of AvaA7 catalyzing denitrification of 3-DAA The high conversion efficiency of 3-AAA (7) to 3-DAA (8
Graphical Abstract
Figure 1: Comparison of ava and cma clusters and the biosynthetic pathway of p-coumaric acid. A) Schematic re...
Figure 2: Heterologous expression of the cma cluster in S. albus. A) Schematic representation of the gene set...
Figure 3: In vitro analysis of Cma proteins. A) In vitro analysis of CmaA1 and CmaA3. Extracted ion chromatog...
Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides
- Kan Tang,
- Megan R. Brown,
- Chad Risko,
- Melissa K. Gish,
- Garry Rumbles,
- Phuc H. Pham,
- Oana R. Luca,
- Stephen Barlow and
- Seth R. Marder
Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142
- . −2 V vs FeCp2+/0, yet the dimers are reasonably stable to air due to the kinetic barriers associated with the coupling of electron-transfer and bond-cleavage reactions [26]. Here we demonstrate that (N-DMBI)2 and (Cyc-DMBI)2 (Figure 1c) can be used to accomplish dehalogenation of benzyl, alkyl, and
Graphical Abstract
Figure 1: (a, b) Schematics of previous approaches to dehalogenation-based reactions using molecular reductan...
Scheme 1: Selective deiodination of 2-iodobenzyl chloride.
Scheme 2: Reaction mechanisms for the reactions of dimeric reductants (D2) such as (Y-DMBI)2 derivatives with...
Figure 2: (a) A representative temporal evolution of % conversion (blue squares), % toluene yield (red diamon...
Figure 3: Top: UV–vis absorption spectra for the two dimeric reductants in THF emphasizing (a) the different ...
Figure 4: Transient absorption spectra of (a) (N-DMBI)2 in MeCN, (b) (N-DMBI)2 in toluene, and (c) (Cyc-DMBI)2...
Anion–π catalysis on carbon allotropes
- M. Ángeles Gutiérrez López,
- Mei-Ling Tan,
- Giacomo Renno,
- Augustina Jozeliūnaitė,
- J. Jonathan Nué-Martinez,
- Javier Lopez-Andarias,
- Naomi Sakai and
- Stefan Matile
Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140
- forward. Decarboxylation of the resulting intermediate IV then affords the chiral addition product 6. This enolate addition is in kinetic competition with simple decarboxylation, yielding thioacetate 7. Under most conditions, this decarboxylation is favored. Anion–π catalysis selectively accelerates the
Graphical Abstract
Figure 1: (A) Anion–π catalysis: Stabilization of anionic transition states from substrate S to product P on ...
Figure 2: Bioinspired enolate addition chemistry to benchmark anion–π catalysts: Stabilization of “enol” inte...
Figure 3: Structure and activity of fullerene-amine dyads to catalyze the intrinsically disfavored but biolog...
Figure 4: Asymmetric anion–π catalysis of intrinsically disfavored exo-selective Diels–Alder reactions on ful...
Figure 5: Asymmetric anion–π catalysis to install remote stereogenic centers on fullerene catalyst 21, with n...
Figure 6: Primary anion–π autocatalysis on monofunctional fullerene 31, with catalytic and autocatalytic rate...
Figure 7: (A) Macrodipoles induced by anionic transition states account for anion–π catalysis on fullerenes. ...
Figure 8: Structure and activity of covalently and non-covalently modified SWCNTs and MWCNTs, with A/D ratios...
Figure 9: (A) Epoxide-opening ether cyclization on pristine carbon nanotubes occurs with (XVI) but not withou...
Figure 10: Electric-field-induced anion–π catalysis on MWCNTs 3 on graphite 76 in electrochemical microfluidic...
Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity
- Swagat K. Mohapatra,
- Khaled Al Kurdi,
- Samik Jhulki,
- Georgii Bogdanov,
- John Bacsa,
- Maxwell Conte,
- Tatiana V. Timofeeva,
- Seth R. Marder and
- Stephen Barlow
Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121
- wide range of semiconductors, they must exhibit low ionization energies and thus air sensitivity. One approach to circumvent this issue is to identify systems where the electron-transfer process is coupled to other chemical reactions, increasing the kinetic stability of the dopant to air, and thus
- previously reported for the Y = cyclohexyl, R = R' = H derivative 1e2 (1.640(4) Å) [14], despite DFT calculations indicating that the former dimer is considerably more weakly bonded [8][14] and kinetic evidence for the “cleavage-first” mechanism occurring in doping reactions using 1b2 but not 1e2 (see below
Graphical Abstract
Figure 1: DMBI+, DMBI-H, and (DMBI)2 derivatives discussed in this work (new compounds in red).
Scheme 1: Synthesis of DMBI-H and (DMBI)2 derivatives and structures of side products.
Figure 2: Crystallographically characterized molecules related to DMBI dimers.
Figure 3: Molecular structures from the single crystal structures of 1b2 (two crystallographically inequivale...
Figure 4: Molecular structures from the single crystal structures of 1bH (upper left), 1gH (upper right), 1hH...
Figure 5: Structures of the cations from the single crystal structures of 1g+I− (left), 1h+PF6− (center), and ...
Figure 6: Cyclic voltammograms (50 mV s−1, THF, 0.1 M Bu4NPF6) of 1g+PF6–, 1gH, and 1g2, in each case contain...
Figure 7: Acceptors used to examine reactivity of DMBI-H and (DMBI)2 derivatives.
Figure 8: a) Temporal evolution of the absorbance at 1030 nm, corresponding to an absorption maximum of VI•–,...
Radical chemistry in polymer science: an overview and recent advances
- Zixiao Wang,
- Feichen Cui,
- Yang Sui and
- Jiajun Yan
Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116
- the DOPA-metal complex helps mussel adhere onto inorganic surfaces (Scheme 3). 1.2 Conventional radical polymerization Radical polymerization, which IUPAC defines as ‘A chain polymerization in which the kinetic-chain carriers are radicals’ [13], is the most widely used reaction in polymer industry. As
- cables are increased from 70 °C to 90 °C and 150 °C to 230 °C, respectively. Besides that, XLPE shows a more rubber-like behavior [126]. As the peroxide crosslinking process is industrially important, multiple kinetic models have been established to understand the reaction between polymers, peroxides
Graphical Abstract
Scheme 1: Oxidation of catechol and subsequent cross-linking. Scheme 1 redrawn from [3].
Scheme 2: (A) Structure of typical urushiol in Chinese lacquer, and (B) schematic process of laccase-catalyze...
Scheme 3: A) Primary amino acid sequence of mfp-1, mfp-3, and mfp-5 (Y: DOPA, K: lysine). B) Scheme showing e...
Scheme 4: Activation–deactivation equilibrium in nitroxide-mediated polymerizations. Bicomponent initiating s...
Scheme 5: Mechanism of a transition metal complex-mediated ATRP. Scheme 5 redrawn from [14].
Scheme 6: Mechanism of RAFT polymerization. Scheme 6 redrawn from [68].
Scheme 7: Degenerative transfer (a) and reversible termination (b) mechanism of OMRP. Scheme 7 redrawn from [70].
Scheme 8: Simplified mechanism of a RITP. Scheme 8 redrawn from [21].
Scheme 9: (A) Structures of π-conjugated conductive polymers. (B) Examples of conductive polymer synthesis vi...
Scheme 10: Possible regiochemical couplings in PATs. Scheme 10 redrawn from [79].
Scheme 11: General thiol-ene photopolymerization process. Scheme 11 redrawn from [81].
Scheme 12: (a) Three generations of Grubbs catalysts. (b) Proposed mechanism for photo-ROMP via a reductive qu...
Scheme 13: Pyrylium and thiopyrylium salts studied by Boydston et al. Scheme 13 redrawn from [91].
Scheme 14: A general illustration of post-polymerization modification by thiol–ene chemistry.
Scheme 15: Introduction of functionalities by nitroxide radical coupling of HO-TEMPO derivatives.
Scheme 16: Chemical reaction process scheme of DCP-induced crosslinking of LDPE. Scheme 16 redrawn from [126].
Scheme 17: A probable mechanism of radical-induced hydrosilylation.
Scheme 18: Polymer surface modification by homolytic dediazonation of diazonium salts.
Scheme 19: Photoinduced polymer surface modification or surface grafting using benzophenone.
Scheme 20: Depolymerization mechanism of common photoresists. (a) A possible mechanism of radiation decomposit...
Scheme 21: Proposed mechanisms of photooxidative depolymerization of polystyrene. (a) Scheme 21a was reprinted with perm...
N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations
- Fatemeh Doraghi,
- Seyedeh Pegah Aledavoud,
- Mehdi Ghanbarlou,
- Bagher Larijani and
- Mohammad Mahdavi
Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106
- an effective catalysis system (Scheme 29) [63]. Kinetic studies in this cross coupling-reaction indicated that N-(arylthio)succinimides 1 with electron-deficient arene 4 undergoe thioarylation catalyzed by Fe(NTf2)3. Related molecules bearing an electron-rich arene showed an autocatalytic pathway
Graphical Abstract
Scheme 1: Sulfur-containing bioactive molecules.
Scheme 2: Scandium-catalyzed synthesis of thiosulfonates.
Scheme 3: Palladium-catalyzed aryl(alkyl)thiolation of unactivated arenes.
Scheme 4: Catalytic cycle for Pd-catalyzed aryl(alkyl)thiolation of unactivated arenes.
Scheme 5: Iron- or boron-catalyzed C–H arylthiation of substituted phenols.
Scheme 6: Iron-catalyzed azidoalkylthiation of alkenes.
Scheme 7: Plausible mechanism for iron-catalyzed azidoalkylthiation of alkenes.
Scheme 8: BF3·Et2O‑mediated electrophilic cyclization of aryl alkynoates.
Scheme 9: Tentative mechanism for BF3·Et2O‑mediated electrophilic cyclization of aryl alkynoates.
Scheme 10: Construction of 6-substituted benzo[b]thiophenes.
Scheme 11: Plausible mechanism for construction of 6-substituted benzo[b]thiophenes.
Scheme 12: AlCl3‑catalyzed cyclization of N‑arylpropynamides with N‑sulfanylsuccinimides.
Scheme 13: Synthetic utility of AlCl3‑catalyzed cyclization of N‑arylpropynamides with N‑sulfanylsuccinimides.
Scheme 14: Sulfenoamination of alkenes with sulfonamides and N-sulfanylsuccinimides.
Scheme 15: Lewis acid/Brønsted acid controlled Pd-catalyzed functionalization of aryl C(sp2)–H bonds.
Scheme 16: Possible mechanism for Lewis acid/Brønsted acid controlled Pd-catalyzed functionalization of aryl C...
Scheme 17: FeCl3-catalyzed carbosulfenylation of unactivated alkenes.
Scheme 18: Copper-catalyzed electrophilic thiolation of organozinc halides.
Scheme 19: h-BN@Copper(II) nanomaterial catalyzed cross-coupling reaction of sulfoximines and N‑(arylthio)succ...
Scheme 20: AlCl3‑mediated cyclization and sulfenylation of 2‑alkyn-1-one O‑methyloximes.
Scheme 21: Lewis acid-promoted 2-substituted cyclopropane 1,1-dicarboxylates with sulfonamides and N-(arylthio...
Scheme 22: Lewis acid-mediated cyclization of β,γ-unsaturated oximes and hydrazones with N-(arylthio/seleno)su...
Scheme 23: Credible pathway for Lewis acid-mediated cyclization of β,γ-unsaturated oximes with N-(arylthio)suc...
Scheme 24: Synthesis of 4-chalcogenyl pyrazoles via chalcogenation/cyclization of α,β-alkynic hydrazones.
Scheme 25: Controllable synthesis of 3-thiolated pyrroles and pyrrolines.
Scheme 26: Possible mechanism for controllable synthesis of 3-thiolated pyrroles and pyrrolines.
Scheme 27: Co-catalyzed C2-sulfenylation and C2,C3-disulfenylation of indole derivatives.
Scheme 28: Plausible catalytic cycle for Co-catalyzed C2-sulfenylation and C2,C3-disulfenylation of indoles.
Scheme 29: C–H thioarylation of electron-rich arenes by iron(III) triflimide catalysis.
Scheme 30: Difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio succinimides.·
Scheme 31: Suggested mechanism for difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio ...
Scheme 32: Synthesis of thioesters, acyl disulfides, ketones, and amides by N-thiohydroxy succinimide esters.
Scheme 33: Proposed mechanism for metal-catalyzed selective acylation and acylthiolation.
Scheme 34: AlCl3-catalyzed synthesis of 3,4-bisthiolated pyrroles.
Scheme 35: α-Sulfenylation of aldehydes and ketones.
Scheme 36: Acid-catalyzed sulfetherification of unsaturated alcohols.
Scheme 37: Enantioselective sulfenylation of β-keto phosphonates.
Scheme 38: Organocatalyzed sulfenylation of 3‑substituted oxindoles.
Scheme 39: Sulfenylation and chlorination of β-ketoesters.
Scheme 40: Intramolecular sulfenoamination of olefins.
Scheme 41: Plausible mechanism for intramolecular sulfenoamination of olefins.
Scheme 42: α-Sulfenylation of 5H-oxazol-4-ones.
Scheme 43: Metal-free C–H sulfenylation of electron-rich arenes.
Scheme 44: TFA-promoted C–H sulfenylation indoles.
Scheme 45: Proposed mechanism for TFA-promoted C–H sulfenylation indoles.
Scheme 46: Organocatalyzed sulfenylation and selenenylation of 3-pyrrolyloxindoles.
Scheme 47: Organocatalyzed sulfenylation of S-based nucleophiles.
Scheme 48: Conjugate Lewis base Brønsted acid-catalyzed sulfenylation of N-heterocycles.
Scheme 49: Mechanism for activation of N-sulfanylsuccinimide by conjugate Lewis base Brønsted acid catalyst.
Scheme 50: Sulfenylation of deconjugated butyrolactams.
Scheme 51: Intramolecular sulfenofunctionalization of alkenes with phenols.
Scheme 52: Organocatalytic 1,3-difunctionalizations of Morita–Baylis–Hillman carbonates.
Scheme 53: Organocatalytic sulfenylation of β‑naphthols.
Scheme 54: Acid-promoted oxychalcogenation of o‑vinylanilides with N‑(arylthio/arylseleno)succinimides.
Scheme 55: Lewis base/Brønsted acid dual-catalytic C–H sulfenylation of aryls.
Scheme 56: Lewis base-catalyzed sulfenoamidation of alkenes.
Scheme 57: Cyclization of allylic amide using a Brønsted acid and tetrabutylammonium chloride.
Scheme 58: Catalytic electrophilic thiocarbocyclization of allenes with N-thiosuccinimides.
Scheme 59: Suggested mechanism for electrophilic thiocarbocyclization of allenes with N-thiosuccinimides.
Scheme 60: Chiral chalcogenide-catalyzed enantioselective hydrothiolation of alkenes.
Scheme 61: Proposed mechanism for chalcogenide-catalyzed enantioselective hydrothiolation of alkenes.
Scheme 62: Organocatalytic sulfenylation for synthesis a diheteroatom-bearing tetrasubstituted carbon centre.
Scheme 63: Thiolative cyclization of yne-ynamides.
Scheme 64: Synthesis of alkynyl and acyl disulfides from reaction of thiols with N-alkynylthio phthalimides.
Scheme 65: Oxysulfenylation of alkenes with 1-(arylthio)pyrrolidine-2,5-diones and alcohols.
Scheme 66: Arylthiolation of arylamines with (arylthio)-pyrrolidine-2,5-diones.
Scheme 67: Catalyst-free isothiocyanatoalkylthiation of styrenes.
Scheme 68: Sulfenylation of (E)-β-chlorovinyl ketones toward 3,4-dimercaptofurans.
Scheme 69: HCl-promoted intermolecular 1, 2-thiofunctionalization of aromatic alkenes.
Scheme 70: Possible mechanism for HCl-promoted 1,2-thiofunctionalization of aromatic alkenes.
Scheme 71: Coupling reaction of diazo compounds with N-sulfenylsuccinimides.
Scheme 72: Multicomponent reactions of disulfides with isocyanides and other nucleophiles.
Scheme 73: α-Sulfenylation and β-sulfenylation of α,β-unsaturated carbonyl compounds.
Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review
- Nosheen Beig,
- Varsha Goyal and
- Raj K. Bansal
Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102
- the simplicity of their synthesis and the modularity of their stereoelectronic properties, NHCs have unquestionably emerged as one of the most fascinating and well-known species in chemical science. The remarkable stability of NHCs can be attributed to both kinetic as well as thermodynamic effects
- structure of an NHC (8) is shown in Figure 1. NHCs having three nitrogen atoms in the five-membered ring, e.g., 1,2,4-triazolylidenes have also been prepared [6]. Both kinetic as well as thermodynamic effects contribute to the remarkable stability of the NHC ring. The presence of bulky substituent groups on
- the nitrogen atoms adjacent to the carbene center result in kinetic stabilization of the NHC suppressing its dimerization to the corresponding olefin (the Wanzlick equilibrium). On the other hand, thermodynamic stabilization results due to donation of lone pair(s) electrons of the adjacent nitrogen
Graphical Abstract
Scheme 1: In situ generation of imidazolylidene carbene.
Scheme 2: Hg(II) complex of NHC.
Scheme 3: Isolable and bottlable carbene reported by Arduengo [3].
Scheme 4: First air-stable carbene synthesized by Arduengo in 1992 [5].
Figure 1: General structure of an NHC.
Figure 2: Stabilization of an NHC by donation of the lone pair electrons into the vacant p-orbital (LUMO) at ...
Figure 3: Abnormal NHC reported by Bertrand [8,9].
Figure 4: Cu(d) orbital to σ*C-N(NHC) interactions in NHC–CuX complexes computed at the B3LYP/def2-SVP level ...
Figure 5: Molecular orbital contributions to the NHC–metal bond.
Scheme 5: Synthesis of NHC–Cu(I) complexes by deprotonation of NHC precursors with a base.
Scheme 6: Synthesis of [NHC–CuX] complexes.
Scheme 7: Synthesis of [(ICy)CuX] and [(It-Bu)CuX] complexes.
Scheme 8: Synthesis of iodido-bridged copper–NHC complexes by deprotonation of benzimidazolium salts reported...
Scheme 9: Synthesis of copper complexes by deprotonation of triazolium salts.
Scheme 10: Synthesis of thiazolylidene–Cu(I) complex by deprotonation with KOt-Bu.
Scheme 11: Preparation of NHC–Cu(I) complexes.
Scheme 12: Synthesis of methylmalonic acid-derived anionic [(26a,b)CuCl]Li(THF)2 and zwitterionic (28) heterol...
Scheme 13: Synthesis of diaminocarbene and diamidocarbene (DAC)–Cu(I) complexes.
Scheme 14: Synthesis of the cationic (NHC)2Cu(I) complex 39 from benzimidazolium salts 38 with tetrakis(aceton...
Scheme 15: Synthesis of NHC and ADC (acyclic diamino carbenes) Cu(I) hexamethyldisilazide complexes reported b...
Scheme 16: Synthesis of NHC–copper(I) complexes using an acetylacetonate-functionalized imidazolium zwitterion...
Scheme 17: Synthesis of NHC–Cu(I) complexes through deprotonation of azolium salts with Cu2O.
Scheme 18: Synthesis of NHC–CuBr complex through deprotonation with Cu2O reported by Kolychev [31].
Scheme 19: Synthesis of chiral NHC–CuBr complexes from phenoxyimine-imidazolium salts reported by Douthwaite a...
Scheme 20: Preparation of linear neutral NHC–CuCl complexes through the use of Cu2O. For abbreviations, please...
Scheme 21: Synthesis of abnormal-NHC–copper(I) complexes by Bertrand, Cazin and co-workers [35].
Scheme 22: Microwave-assisted synthesis of thiazolylidene/benzothiazolylidene–CuBr complexes by Bansal and co-...
Scheme 23: Synthesis of NHC–CuX complexes through transmetallation.
Scheme 24: Preparation of six- or seven-membered NHC–Cu(I) complexes through transmetalation from Ag(I) comple...
Scheme 25: Synthesis of 1,2,3-triazolylidene–CuCl complexes through transmetallation of Ag(I) complexes genera...
Scheme 26: Synthesis of NHC–copper complexes having both Cu(I) and Cu(II) units through transmetalation report...
Scheme 27: Synthesis of new [(IPr(CH2)3Si(OiPr)3)CuX] complexes and anchoring on MCM-41.
Scheme 28: Synthesis of bis(trimethylsilyl)phosphide–Cu(I)–NHC complexes through ligand displacement.
Scheme 29: Synthesis of silyl- and stannyl [(NHC)Cu−ER3] complexes.
Scheme 30: Synthesis of amido-, phenolato-, thiophenolato–Cu(NHC) complexes.
Scheme 31: Synthesis of first isolable NHC–Cu–difluoromethyl complexes reported by Sanford et al. [44].
Scheme 32: Synthesis of NHC–Cu(I)–bifluoride complexes reported by Riant, Leyssens and co-workers [45].
Scheme 33: Conjugate addition of Et2Zn to enones catalyzed by an NHC–Cu(I) complex reported by Woodward in 200...
Scheme 34: Hydrosilylation of a carbonyl group.
Scheme 35: NHC–Cu(I)-catalyzed hydrosilylation of ketones reported by Nolan et al. [48,49].
Scheme 36: Application of chiral NHC–CuCl complex 104 for the enantioselective hydrosilylation of ketones.
Scheme 37: Hydrosilylation reactions catalyzed by NHC–Cu(Ot-Bu) complexes.
Scheme 38: NHC–CuCl catalyzed carbonylative silylation of alkyl halides.
Scheme 39: Nucleophilic conjugate addition to an activated C=C bond.
Figure 6: Molecular electrostatic potential maps (MESP) of two NHC–CuX complexes computed at the B3LYP/def2-S...
Scheme 40: Conjugate addition of Grignard reagents to 3-alkyl-substituted cyclohexenones catalyzed by a chiral...
Scheme 41: NHC–copper complex-catalyzed conjugate addition of Grignard reagent to 3-substituted hexenone repor...
Scheme 42: Conjugate addition or organoaluminum reagents to β-substituted cyclic enones.
Scheme 43: Conjugate addition of boronates to acyclic α,β-unsaturated carboxylic esters, ketones, and thioeste...
Scheme 44: NHC–Cu(I)-catalyzed hydroboration of an allene reported by Hoveyda [63].
Scheme 45: Conjugate addition of Et2Zn to cyclohexenone catalyzed by NHC–Cu(I) complex derived from benzimidaz...
Scheme 46: Asymmetric conjugate addition of diethylzinc to 3-nonen-2-one catalyzed by NHC–Cu complexes derived...
Scheme 47: General scheme of a [3 + 2] cycloaddition reaction.
Scheme 48: [3 + 2] Cycloaddition of azides with alkynes catalyzed by NHC–Cu(I) complexes reported by Diez-Gonz...
Scheme 49: Application of NHC–CuCl/N-donor combination to catalyze the [3 + 2] cycloaddition of benzyl azide w...
Scheme 50: [3 + 2] Cycloaddition of azides with acetylenes catalyzed by bis(NHC)–Cu complex 131 and mixed NHC–...
Figure 7: NHC–CuCl complex 133 as catalyst for the [3 + 2] cycloaddition of alkynes with azides at room tempe...
Scheme 51: [3 + 2] Cycloaddition of a bulky azide with an alkynylpyridine using [(NHC)Cu(μ-I)2Cu(NHC)] copper ...
Scheme 52: [3 + 2] Cycloaddition of benzyl azide with phenylacetylene under homogeneous and heterogeneous cata...
Scheme 53: [3 + 2] Cycloaddition of benzyl azide with acetylenes catalyzed by bisthiazolylidene dicopper(I) co...
Figure 8: Copper (I)–NHC linear coordination polymer 137 and its conversion into tetranuclear (138) and dinuc...
Scheme 54: An A3 reaction.
Scheme 55: Synthesis of SiO2-immobilized NHC–Cu(I) catalyst 141 and its application in the A3-coupling reactio...
Scheme 56: Preparation of dual-purpose Ru@SiO2–[(NHC)CuCl] catalyst system 142 developed by Bordet, Leitner an...
Scheme 57: Application of the catalyst system Ru@SiO2–[Cu(NHC)] 142 to the one-pot tandem A3 reaction and hydr...
Scheme 58: A3 reaction of phenylacetylene with secondary amines and aldehydes catalyzed by benzothiazolylidene...
Figure 9: Kohn–Sham HOMOs of phenylacetylene and NHC–Cu(I)–phenylacetylene complex computed at the B3LYP/def2...
Figure 10: Energies of the FMOs of phenylacetylene, iminium ion, and NHC–Cu(I)–phenylacetylene complex compute...
Scheme 59: NHC–Cu(I) catalyzed diboration of ketones 147 by reacting with bis(pinacolato)diboron (148) reporte...
Scheme 60: Protoboration of terminal allenes catalyzed by NHC–Cu(I) complexes reported by Hoveyda and co-worke...
Scheme 61: NHC–CuCl-catalyzed borylation of α-alkoxyallenes to give 2-boryl-1,3-butadienes.
Scheme 62: Regioselective hydroborylation of propargylic alcohols and ethers catalyzed by NHC–CuCl complexes 1...
Scheme 63: NHC–CuOt-Bu-catalyzed semihydrogenation and hydroborylation of alkynes.
Scheme 64: Enantioselective NHC–Cu(I)-catalyzed hydroborations of 1,1-disubstituted aryl olefins reported by H...
Scheme 65: Enantioselective NHC–Cu(I)-catalyzed hydroboration of exocyclic 1,1-disubstituted alkenes reported ...
Scheme 66: Markovnikov-selective NHC–CuOH-catalyzed hydroboration of alkenes and alkynes reported by Jones et ...
Scheme 67: Dehydrogenative borylation and silylation of styrenes catalyzed by NHC–CuOt-Bu complexes developed ...
Scheme 68: N–H/C(sp2)–H carboxylation catalyzed by NHC–CuOH complexes.
Scheme 69: C–H Carboxylation of benzoxazole and benzothiazole derivatives with CO2 using a 1,2,3-triazol-5-yli...
Scheme 70: Use of Cu(I) complex derived from diethylene glycol-functionalized imidazo[1,5,a] pyridin-3-ylidene...
Scheme 71: Allylation and alkenylation of polyfluoroarenes and heteroarenes catalyzed by NHC–Cu(I) complexes r...
Scheme 72: Enantioselective C(sp2)–H allylation of (benz)oxazoles and benzothiazoles with γ,γ-disubstituted pr...
Scheme 73: C(sp2)–H arylation of arenes catalyzed by dual NHC–Cu/NHC–Pd catalytic system.
Scheme 74: C(sp2)–H Amidation of (hetero)arenes with N-chlorocarbamates/N-chloro-N-sodiocarbamates catalyzed b...
Scheme 75: NHC–CuI catalyzed thiolation of benzothiazoles and benzoxazoles.
Synthesis of ether lipids: natural compounds and analogues
- Marco Antônio G. B. Gomes,
- Alicia Bauduin,
- Chloé Le Roux,
- Romain Fouinneteau,
- Wilfried Berthe,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
- sodium cyanoborohydride and trifluoroacetic acid to yield the thermodynamic product 32.4 or sodium cyanoborohydride and trimethylchlorosilane (a bulkier reagent) that favor the formation of the kinetic product 32.3 (Figure 32). Then, a quite similar sequence (the order was different) can be applied to
Graphical Abstract
Figure 1: Chemical structure of some natural ether lipids (ELs).
Figure 2: Synthesis of lyso-PAF and PAF from 1-O-alkylglycerol [64].
Figure 3: Synthesis of lyso-PAF from 1,3-benzylideneglycerol 3.1 [69].
Figure 4: A) Synthesis of the two enantiomers of octadecylglycerol (4.6 and 4.10) from ᴅ-mannitol (4.1); B) s...
Figure 5: Four-step synthesis of PAF 5.6 from (S)-glycidol [73].
Figure 6: Synthesis of 1-O-alkylglycerol A) from solketal, B) from ᴅ- or ʟ-tartaric acid and the intermediate ...
Figure 7: Synthesis of EL building blocks starting from substituted glycidol 7.1a–c [82].
Figure 8: Synthesis of PAF 8.5 by using phosphoramidite 8.2 [86].
Figure 9: Synthesis of oleyl-PAF 9.7 from ʟ-serine [88].
Figure 10: Synthesis of racemic analogues of lyso-PAF 10.8 and PAF 10.9 featuring a phenyl group between the g...
Figure 11: Synthesis of racemic deoxy-lyso-PAF 11.7 and deoxy-PAF 11.8 [91].
Figure 12: Synthesis of racemic thio-PAF 12.8 [93].
Figure 13: Racemic synthesis of 13.6 to illustrate the modification of the glycerol backbone by adding a methy...
Figure 14: Racemic synthesis of 14.5 as an illustration of the introduction of methyl substituents on the glyc...
Figure 15: Synthesis of functionalized sn-2-acyl chains of PC-EL; A) Steglich esterification or acylation reac...
Figure 16: Synthesis of racemic mc-PAF (16.3), a carbamate analogue of PAF [102].
Figure 17: A) Synthesis of (R)-17.2 and (S)-17.6 starting from (S)-solketal (17.1); B) synthesis of N3-PAF (17...
Figure 18: Modification of the phosphocholine polar head to produce PAF analogues [81].
Figure 19: Racemic PAF analogues 19.3 and 19.5 characterized by the absence of the phosphate group [107].
Figure 20: Synthesis of PIP3-PAF (20.7) [108].
Figure 21: Large-scale synthesis of C18-edelfosine (21.8) [116].
Figure 22: Synthesis of C16-edelfosine (22.10) starting from isopropylidene-ʟ-glyceric acid methyl ester (22.1...
Figure 23: Phosphocholine moiety installation by the use of chlorophosphite 23.2 as key reagent [119].
Figure 24: Synthesis of rac-1-alkyl-2-O-methylglycerol (AMG) [120].
Figure 25: Synthesis of stereocontrolled 1-alkyl-2-O-methyl glycerol 25.9 (AMG) from dimethyl ᴅ-tartrate [81].
Figure 26: A) Racemic synthesis of thioether 26.4 [129,130], B) structure of sulfone analogue 26.5 [129].
Figure 27: Stereocontrolled synthesis of C18-edelfosine thioether analogue 27.8 [118].
Figure 28: Synthesis of thioether 28.4 that include a thiophosphate function [134].
Figure 29: Synthesis of ammonium thioether 29.4 and 29.6 [135].
Figure 30: Synthesis of the N-methylamino analogue of edelfosine 30.6 (BN52211) [138].
Figure 31: Synthesis of 1-desoxy analogues of edelfosine; A) with a saturated alkyl chain; B) synthesis of the...
Figure 32: Stereocontrolled synthesis of edelfosine analogue (S)-32.8 featuring a C18:1 lipid chain [142].
Figure 33: Synthesis of edelfosine analogues with modulation of the lipid chain; A) illustration with the synt...
Figure 34: Synthesis of phospholipid featuring a carbamate function to link the lipid chain to the glycerol un...
Figure 35: Synthesis of sesquiterpene conjugates of phospho glycero ether lipids [148].
Figure 36: Racemic synthesis of methyl-substituted glycerol analogues 36.7 and 36.10: A) synthesis of diether ...
Figure 37: Racemic synthesis of ilmofosine (37.6) [155,156].
Figure 38: A) Stereoselective synthesis of 38.5 via a stereoselective hydroboration reaction; B) synthesis of ...
Figure 39: Racemic synthesis of SRI62-834 (39.6) featuring a spiro-tetrahydrofurane heterocycle in position 2 ...
Figure 40: Racemic synthesis of edelfosine analogue 40.5 featuring an imidazole moiety in sn-2 position [160].
Figure 41: Racemic synthesis of fluorine-functionalized EL: A) Synthesis of 41.6 and B) synthesis of 41.8 [161-163].
Figure 42: A) Synthesis of the β-keto-ester 42.6 that also features a decyl linker between the phosphate and t...
Figure 43: Synthesis of phosphonate-based ether lipids; A) edelfosine phosphonate analogue 43.7 and B) thioeth...
Figure 44: Enantioselective synthesis of phosphonates 44.3 and 44.4 [171].
Figure 45: Racemic synthesis of phosphinate-based ether lipid 45.10 [172].
Figure 46: Racemic synthesis of edelfosine arsonium analogue 46.5 [173].
Figure 47: Synthesis of edelfosine dimethylammonium analogue 47.2 [118].
Figure 48: Synthesis of rac-C18-edelfosine methylammonium analogue 48.4 [176].
Figure 49: A) Synthesis of edelfosine N-methylpyrrolidinium analogue 49.2 or N-methylmorpholinium analogue 49.3...
Figure 50: A) Synthesis of edelfosine’s analogue 50.4 with a PE polar group; B) illustration of a pyridinium d...
Figure 51: A) Synthesis of 51.4 featuring a thiazolium cationic moiety; B) synthesis of thiazolium-based EL 51...
Figure 52: Synthesis of cationic ether lipids 52.3, 52.4 and 52.6 [135,183].
Figure 53: Synthesis of cationic carbamate ether lipid 53.5 [184].
Figure 54: Synthesis of cationic sulfonamide 54.5 [185].
Figure 55: Chemical structure of ONO-6240 (55.1) and SRI-63-119 (55.2).
Figure 56: Synthesis of non-ionic ether lipids 56.2–56.9 [188].
Figure 57: Synthesis of ether lipid conjugated to foscarnet 57.6 [189].
Figure 58: A) Synthesis of ether lipid conjugated to arabinofuranosylcytosine; B) synthesis of AZT conjugated ...
Figure 59: Synthesis of quercetin conjugate to edelfosine [191].
Figure 60: Synthesis of 60.8 (Glc-PAF) [194].
Figure 61: A) Synthesis of amino ether lipid 61.7 functionalized with a rhamnose unit and its amide analogue 6...
Figure 62: A) Synthesis of glucose ether lipid 62.4; B) structure of ether lipid 62.5 possessing a maltose uni...
Figure 63: A) Synthesis of glucuronic methyl ester 63.8; B) structure of cellobiose 63.9 and maltose 63.10 ana...
Figure 64: A) Synthesis of maltosyl glycerolipid 64.7; B) structure of lactose analogue 64.8 prepared followin...
Figure 65: A) Asymmetric synthesis of the aglycone moiety starting from allyl 4-methoxyphenyl ether; B) glycos...
Figure 66: A) Synthesis of ohmline possessing a lactose moiety. B) Structure of other glyco glycero lipids pre...
Figure 67: A) Synthesis of lactose-glycerol ether lipid 67.5; B) analogues possessing a maltose (67.6) or meli...
Figure 68: Synthesis of digalactosyl EL 68.6, A) by using trityl, benzyl and acetyl protecting groups, B) by u...
Figure 69: A) Synthesis of α-ohmline; B) structure of disaccharide ether lipids prepared by using similar meth...
Figure 70: Synthesis of lactose ether lipid 70.3 and its analogue 70.6 featuring a carbamate function as linke...
Figure 71: Synthesis of rhamnopyranoside diether 71.4 [196].
Figure 72: Synthesis of 1-O-hexadecyl-2-O-methyl-3-S-(α-ᴅ-1'-thioglucopyranosyl)-sn-glycerol (72.5) [225].
Figure 73: A) Preparation of lipid intermediate 73.4; B) synthesis of 2-desoxy-C-glycoside 73.10 [226].
Figure 74: Synthesis of galactose-pyridinium salt 74.3 [228].
Figure 75: Synthesis of myo-inositol derivative Ino-C2-PAF (75.10) [230].
Figure 76: A) Synthesis of myo-inositol phosphate building block 76.7; B) synthesis of myo-inositolphosphate d...
Figure 77: A) Synthesis of phosphatidyl-3-desoxy-inositol 77.4; B) synthesis of phosphono-3-desoxyinositol 77.9...
Figure 78: A) Structure of diether phosphatidyl-myo-inositol-3,4-diphosphate 78.1; B) synthesis of phosphatidy...
Figure 79: A) Synthesis of diether-phosphatidyl derivative 79.4 featuring a hydroxymethyl group in place of a ...
Figure 80: Synthesis of Glc-amine-PAF [78].
Figure 81: Synthesis of glucosamine ether lipid 81.4 and its analogues functionalized in position 3 of the ami...
Figure 82: Synthesis of fully deprotected aminoglucoside ether lipid 82.5 [246].
Figure 83: Synthesis of C-aminoglycoside 83.12 using Ramberg–Bäcklund rearrangement as a key step [250].
Figure 84: A) List of the most important glyco lipids and amino glyco lipids included in the study of Arthur a...
Figure 85: Synthesis of mannosamine ether lipid 85.6 [254].
Figure 86: A) Synthesis of glucosamine ether lipids with a non-natural ʟ-glucosamine moiety; B) synthesis of e...
Figure 87: A) Structure of the most efficient anticancer agents 87.1–87.4 featuring a diamino glyco ether lipi...
Figure 88: A) Synthesis of diamino glyco ether lipid 87.4; B) synthesis of bis-glycosylated ether lipid 88.10 [256]....
Figure 89: Synthesis of triamino ether lipid 89.4 [260].
Figure 90: Synthesis of chlorambucil conjugate 90.7 [261].
Figure 91: Three main methods for the preparation of glycerol ether lipid 91.3; A) from solketal and via a tri...
Figure 92: Four different methods for the installation of the phosphocholine polar head group; A) method using...
Figure 93: Illustration of two methods for the installation of saccharides or aminosaccharides; A) O-glycosyla...
Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control
- Carlee A. Montgomery and
- Graham K. Murphy
Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86
- formation of 33 and 35, implying that single electron-transfer processes were occurring. Also, a competition experiment between 32 and [D6]-32 gave a competitive intermolecular kinetic isotope effect of 9.5 that suggested an N-Me proton abstraction was the rate determining step. Given this, the authors
- ]. The authors discounted a free carbene-based C–H insertion because conducting the reaction in the presence of the radical trap phenyl N-tert-butyl nitrone (PBN) and the radical scavenger TEMPO resulted in decreased yields and isolation of their iodonium ylide adducts. Additional kinetic isotope effect
Graphical Abstract
Figure 1: Generic representation of halogen bonding.
Figure 2: Quantitative evaluation of σ-holes in monovalent iodine-containing compounds; and, qualitative mole...
Figure 3: Quantitative evaluation of σ-holes in hypervalent iodine-containing molecules; and, qualitative MEP...
Figure 4: Quantitative evaluation of σ-holes in iodonium ylides; and, qualitative MEP map of I-12 from −0.083...
Scheme 1: Outline of possible reaction pathways between iodonium ylides and Lewis basic nucleophiles (top); a...
Scheme 2: Metal-free cyclopropanations of iodonium ylides, either as intermolecular (a) or intramolecular pro...
Figure 5: Zwitterionic mechanism for intramolecular cyclopropanation of iodonium ylides (left); and, stepwise...
Scheme 3: Metal-free intramolecular cyclopropanation of iodonium ylides.
Figure 6: Concerted cycloaddition pathway for the metal-free, intramolecular cyclopropanation of iodonium yli...
Scheme 4: Reaction of ylide 6 with diphenylketene to form lactone 24 and 25.
Figure 7: Nucleophilic (top) and electrophilic (bottom) addition pathways proposed by Koser and Hadjiarapoglo...
Scheme 5: Indoline synthesis from acyclic iodonium ylide 31 and tertiary amines.
Scheme 6: N-Heterocycle synthesis from acyclic iodonium ylide 31 and secondary amines.
Figure 8: Proposed mechanism for the formation of 33a from iodonium ylides and amines, involving an initial h...
Scheme 7: Indoline synthesis from acyclic iodonium ylides 39 and tertiary amines under blue light photocataly...
Scheme 8: Metal-free cycloproponation of iodonium ylides under blue LED irradiation. aUsing trans-β-methylsty...
Figure 9: Proposed mechanism of the cyclopropanation between iodonium ylides and alkenes under blue LED irrad...
Scheme 9: Formal C–H alkylation of iodonium ylides by nucleophilic heterocycles under blue LED irradiation.
Figure 10: Proposed mechanism of the formal C–H insertion of pyrrole under blue LED irradiation.
Scheme 10: X–H insertions between iodonium ylides and carboxylic acids, phenols and thiophenols.
Figure 11: Mechanistic proposal for the X–H insertion reactions of iodonium ylides.
Scheme 11: Radiofluorination of biphenyl using iodonium ylides 54a–e derived from various β-dicarbonyl auxilia...
Scheme 12: Radiofluorination of arenes using spirocycle-derived iodonium ylides 56.
Scheme 13: Radiofluorination of arenes using SPIAd-derived iodonium ylides 58.
Figure 12: Calculated reaction coordinate for the radiofluorination of iodonium ylide 60.
Scheme 14: Radiofluorination of iodonium ylides possessing various ortho- and para-substituents on the iodoare...
Figure 13: Difference in Gibbs activation energy for ortho- or para-anisyl derived iodonium ylides 63a and 63b....
Figure 14: Proposed equilibration of intermediates to transit between 64a (the initial adduct formed between 6...
Scheme 15: Comparison of 31 and ortho-methoxy iodonium ylide 39 in rhodium-catalyzed cyclopropanation and cycl...
Figure 15: X-ray crystal structure of dimeric 39 [6], (CCDC# 893474) [143,144].
Scheme 16: Enaminone synthesis using diazonium and iodonium ylides.
Figure 16: Transition state calculations for enaminone synthesis from iodonium ylides and thioamides.
Scheme 17: The reaction between ylides 73a–f and N-methylpyrrole under 365 nm UV irradiation.
Figure 17: Crystal structures of 76c (top) and 76e (bottom) [101], (CCDC# 2104180 & 2104181) [143,144].
Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light
- Damiano Diprima,
- Hannes Gemoets,
- Stefano Bonciolini and
- Koen Van Aken
Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82
- irradiation (e.g., at 405 or 455 nm) no conversion was observed (Table 1, entries 8 and 9). Finally, the effect of the light intensity was investigated irradiating at 365 nm and it turned out to largely effect the kinetic of the reaction (see Supporting Information File 1, Figure S3). In general, the presence
Graphical Abstract
Scheme 1: Oxidation of heteroatoms.
Scheme 2: Graphical representation comparing A electrochemistry and B photoredox catalysis using a semiconduc...
Figure 1: Study of additives. A) Effect of the addition of 1 equiv of various acids and bases to the standard...
Scheme 3: Substrate scope with reaction times and isolated yields. 1 mmol (1 equiv) substrate was reacted in ...
Scheme 4: Setup used in the flow experiment for the triphenylphosphine oxidation.
Scheme 5: Proposed extra alternative pathway.
Photoredox catalysis harvesting multiple photon or electrochemical energies
- Mattia Lepori,
- Simon Schmid and
- Joshua P. Barham
Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads
- Liyuan Cao,
- Xi Liu,
- Xue Zhang,
- Jianzhang Zhao,
- Fabiao Yu and
- Yan Wan
Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79
- (Figure 7). Taking the NI-PTZ-F as an example, the transient absorption spectra measured in HEX and the evolution associated difference spectra (EADS), obtained by global fitting based on sequential kinetic model, are presented (Figure 7a and 7b). The first transient species (black line in Figure 7b) is
- spectrograph and to the detector. The sample was contained in a 1 mm quartz cuvette mounted on a movable stage, in order to avoid photodecomposition. The data were subdivided in two different time intervals and fitted using the Glotaran-Application 1.5.1 and Surface Xplorer software. The number of kinetic
- photolysis spectrometer (Edinburgh Instruments, Ltd., U.K.). The data (kinetic decay traces and the transient difference absorption spectra) were analyzed with the L900 software. All samples were deaerated with N2 for ca. 15 min before measurement and excited with a nanosecond pulsed laser (OPO nanosecond
Graphical Abstract
Scheme 1: Synthesis of the compounds. Conditions: (a) 4-fluoroaniline, acetic acid, N2, reflux, 7 h, yield: 7...
Figure 1: UV–vis absorption spectra of (a) NI-PTZ-F, NI-PTZ-Ph, NI-PTZ-CH3, NI-PTZ-OCH3, and NI-PTZ-C5 and (b...
Figure 2: Fluorescence spectra of the dyads. (a) NI-PTZ-F, (b) NI-PTZ-Ph, (c) NI-PTZ-CH3, (d) NI-PTZ-OCH3, (e...
Figure 3: Fluorescence spectra of the dyads. (a) NI-PTZ-F, (b) NI-PTZ-Ph, (c) NI-PTZ-CH3, (d) NI-PTZ-OCH3, (e...
Figure 4: Fluorescence lifetime of (a) NI-PTZ-F; (b) NI-PTZ-Ph; (c) NI-PTZ-CH3; (d) NI-PTZ-OCH3 (λem = 610 nm...
Figure 5: Cyclic voltammograms of the compounds. (a) NI-PTZ-F; NI-PTZ-Ph; NI-PTZ-CH3; NI-PTZ-OCH3; NI-PTZ-C5 ...
Figure 6: Thermogravimetric analysis curves of NI-PTZ-F, NI-PTZ-Ph, NI-PTZ-CH3, NI-PTZ-OCH3, NI-PTZ-F-O, and ...
Figure 7: Femtosecond transient absorption spectra of NI-PTZ-F. (a) Transient absorption spectra and (b) the ...
Figure 8: Nanosecond transient absorption spectra of NI-PTZ-F in deaerated solvents of (a) HEX (c = 2.0 × 10−5...
Figure 9: Nanosecond transient absorption spectra of (a) NI-PTZ-F-O (c = 4.0 × 10−5 M), (b) NI-PTZ-Ph-O (c = ...
Figure 10: Optimized ground state geometry of (a) NI-PTZ-F, (b) NI-PTZ-Ph, (c) NI-PTZ-CH3, (d) NI-PTZ-OCH3, (e...
Figure 11: Spin density surfaces of the dyads in the T1 state (gas phase) of (a) NI-PTZ-F, (b) NI-PTZ-Ph, (c) ...
Figure 12: Selected frontier molecular orbitals of NI-PTZ-F, NI-PTZ-Ph, NI-PTZ-C5, NI-PTZ-F-O, NI-PTZ-Ph-O, an...
Scheme 2: Simplified Jablonski diagram of (a) NI-PTZ-F and (b) NI-PTZ-F-O. The 1LE state (1[NI–PTZ–F–O]*) ene...
CO2 complexation with cyclodextrins
- Cecilie Høgfeldt Jessen,
- Jesper Bendix,
- Theis Brock Nannestad,
- Heloisa Bordallo,
- Martin Jæger Pedersen,
- Christian Marcus Pedersen and
- Mikael Bols
Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78
- small value, which means that even at a partial pressure of 5 bar less than 1/2 the CD cavity is filled. The rationale for the poor binding is probably the large discrepancy between the size of CO2 and the CD cavity. 1 has a cavity of 174 Å3 while CO2 is a very small molecule with kinetic diameter of
Graphical Abstract
Figure 1: Structure of cyclodextrins 1–6 studied in this work.
Figure 2: X-ray crystal structure of CO2 bound to α-CD.
Figure 3: TGA curve (blue) and dTGA curve (red) for CO2-1 crystals. Two lumps are seen with the former predom...
Figure 4: Cell used to measure vis spectra under pressure (left), structure of 7 (middle) and spectrum of 7 (...
Figure 5: Binding of CO2 to 1 as a function of pressure.
Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine
- Alessio Regni,
- Francesca Bartoccini and
- Giovanni Piersanti
Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70
- the importance of steric effects [99]. Indeed, while the addition of the nucleophilic α-amino radical to the α-styrenyl position affords the 6-membered ring (kinetic product via intramolecular 6-exo-trig ring closure) [100] the resulting radical is unstabilized, the 7-membered ring (obtained via
Graphical Abstract
Figure 1: (a) Transformations of DMAT to different classes of ergot alkaloids. (b) and (c) Strategies for the...
Scheme 1: Synthesis of compound 5.
Scheme 2: Photoredox-catalyzed radical decarboxylative cyclization of 5.
Figure 2: Proposed reaction mechanism for photoredox-catalyzed radical decarboxylative cyclization.
Scheme 3: Synthesis of tryptophan derivatives 8 and 10.
Figure 3: Proposed reaction mechanism for photoredox-catalyzed radical decarboxylative cyclization.
Scheme 4: Methylation of 11 and the formal total synthesis of (±)-6,7-secoagroclavine.
Pyridine C(sp2)–H bond functionalization under transition-metal and rare earth metal catalysis
- Haritha Sindhe,
- Malladi Mounika Reddy,
- Karthikeyan Rajkumar,
- Akshay Kamble,
- Amardeep Singh,
- Anand Kumar and
- Satyasheel Sharma
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
- . Review C–H Alkylation of pyridine The C–H bond is the backbone of an organic molecule and the conversion of a C–H bond to a C–X bond (X = carbon or heteroatom) forms the basis in organic synthesis. The functionalization of C–H bonds is challenging due to a large kinetic barrier for C–H bond cleavage and
- also found to have a higher catalytic activity for the ortho-alkylation of pyridines with styrenes to give the linear alkylated products (5b,c, Scheme 2). Further, the authors proposed that the C–H bond activation could be the rate limiting step based on kinetic isotope experiments (KIE). The proposed
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?
- Lukáš Marek,
- Jiří Váňa,
- Jan Svoboda and
- Jiří Hanusek
Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61
- MeCN undergoes a ring transformation [1][2] to give 2-phenyl-5-(2-aminophenyl)-4-hydroxy-1,3-thiazole (17') (Scheme 7) under kinetic control, the analogous intermediary hydroxythiazole 7a (Scheme 3) does not decompose into analogous thiazole 7a' due to much worse nucleofugality of the leaving amine
- thiobenzamide, thioacetamide, and thiobenzanilide. Reaction of N-phenyl- and N-methyl-2-bromo(phenyl)acetamide (4a,b) with thiobenzamide in acetonitrile. Transformation of salt 15 under kinetic and thermodynamic control conditions [1]. Reaction of salt 6a under different reaction conditions. Reaction of salt 2b
Graphical Abstract
Scheme 1: Eschenmoser coupling reaction between 3-substituted oxindoles and thioamides.
Scheme 2: Possible reactions of α-haloketones, esters and amides with primary thioamides.
Figure 1: Studied α-bromoamides and α-bromolactams.
Scheme 3: Reaction of 4-bromo-1,1-dimethyl-1,4-dihydroisoquinolin-3(2H)-one (2b) with thiobenzamide and thioa...
Scheme 4: Reaction of 4-bromo-1,1-dimethyl-1,4-dihydroisoquinolin-3(2H)-one (2b) with 4’-substituted thiobenz...
Scheme 5: Reaction of 4-bromoisoquinoline-1,3(2H,4H)-dione (3) with thiobenzamide, thioacetamide, and thioben...
Scheme 6: Reaction of N-phenyl- and N-methyl-2-bromo(phenyl)acetamide (4a,b) with thiobenzamide in acetonitri...
Scheme 7: Transformation of salt 15 under kinetic and thermodynamic control conditions [1].
Figure 2: Comparison of energy profiles (relative Gibbs energies at 298 K in kJ·mol−1 for the ECR (right) and...
