Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• gramicidin S synthetase GrsB [44]. Combined with the peptidyl carrier protein, GrsB PCP-TE was tested by using corresponding pentapeptides NAC thioester and thiophenol thioester, which led to the formation of the desired cyclic decapeptide lactam gramicidin S (9) through a sequential dimerization and

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• dimerization of radical 76. Reaction between radical 9 and species 78 affords boronic ester 79 while returning boryl radical 76. Finally, chain propagation takes place via reaction of 76 with another equivalent of the NHPI ester 3. The Baran lab has recently published a complementary electrochemical method

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• this situation. Acenes are a class of aromatic compounds composed of linearly fused benzene rings, which can be regarded as the narrowest graphene nanoribbons. They are highly promising p-type organic semiconductors, but suffer from insolubility and instability leading to dimerization and/or

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

• (CIIAE), FUNDECYT-PCTEx, Polytechnic School of Caceres Building, Office CIIAE-C7, Av. Universidad s/n, 10003 Cáceres, Spain 10.3762/bjoc.20.10 Abstract Fullerene dimerization inside a peapod is analyzed at DFT level by characterizing the stationary points and deriving the energy profile of the initial

• metadynamics simulations provide hints on structures for the initial steps of the irreversible phase 2 where bond formation and breaking lead to important structural reorganizations within the coalescence process. Keywords: DFT; dimerization; fullerene; molecular dynamics; peapods; Introduction Transmission

• have been published that record the dynamic behavior of a wide range of molecules and chemical reactions. One such process was the dimerization of C60 fullerene in a carbon nanotube peapod, i.e., hybrid structures consisting of fullerene molecules encapsulated in single-walled carbon nanotubes (SWCNT

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• pyrrole unit to one of the dithiole rings of an IF-TTF, allowing for dimerization of extended TTFs via the nitrogen atom by different linkers [14]. Donor–acceptor chromophores can be obtained by replacing one of the dithiafulvene (DTF) rings of the IF-TTF by an electron acceptor. Cyclic and acyclic

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

• ; reduction; reductive dimerization; Introduction Reductive dehalogenation reactions of organic halides can be used in organic synthesis as a means of generating carbon-centered radical or anion intermediates and could have relevance to the treatment of waste halogenated polymers. While such reactions can be

• -containing catalysts [32]. We note that another all-organic reductive dimerization of benzyl halides using 2,3,5,6-tetrakis(tetramethylguanidino)pyridine has recently been reported [37]. The less readily reduced halides examined here (1d,e, and 2) are only sluggishly converted, even when using both (N-DMBI)2

• either dimerization of 2R• or by a second reduction of R• to R− (as invoked in the reductive cyclization of (2-halophenyl)propanoic esters [2]) which then acts as a nucleophile towards a second molecule of RX. However, addition of Me3SiCl to a photoirradiated BnBr/(N-DMBI)2 reaction mixture did not lead

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• acenes exhibit increased reactivity, readily undergoing processes of oxidation and dimerization, consequently disrupting the molecular conjugation [4]. This instability poses a significant obstacle in their widespread application across various devices [4]. The decline in stability seen in larger acenes

• approaches have gained popularity for synthesizing biphenylene derivatives [23]. The utilization of in-situ aryne synthesis to generate biphenylene through the dimerization of arynes 2 from diverse substrates has gained popularity. However, this approach occasionally gives rise to the production of high

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• -pyrazolo[3,4-d]pyrimidin-5-amine followed by dimerization to give the final macrocycle. A convenient synthesis of the latter starting from 4-imino-2-methyl-2,4-dihydro-5H-pyrazolo[3,4-d]pyrimidin-5-amine was developed. A plausible pathway for the macrocycle self-assembly is discussed. Some features of the

• conversion to pyrazolopyrimidine 8. Slow dimerization of compound 8 results in macrocycle 5. The formation of 5 through pyrazolopyrimidine 8 is confirmed by the literature data [40] that the reaction of 4 with N2H4∙H2O in EtOH to give 8 proceeds under much milder conditions than the reaction to afford 5 (rt

• model showed that (Z)-8 was significantly less stable than the s-cis-conformer of 9 in DMSO solution (ΔG = 7.17 kcal/mol; 298 K, 1 atm). As we proposed, pyrazolopyrimidine 8 undergoes dimerization to produce macrocycle 5 under certain conditions (Scheme 5). The dimerization of 8 was thoroughly studied

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

• -1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole, has been obtained from addition of HPO3Et2 across the central C=C bond of bis(1,3-dimethylbenzoimidazolinidin-2-ylidene) [25], 12 dimers have generally been obtained by reductive electrochemical or chemical dimerization of 1+ cations

• compounds of the same classes [9][13][19][24], and the redox potentials are summarized in Table 1. The cations exhibit features assigned to E(1+/1•) that are non-reversible owing to the rapid dimerization of 1•. These values are important in determining the overall thermodynamic reducing power of the dimers

• spin resonance [14] or using dissociation and dimerization barriers from reaction kinetics and variable scan-rate electrochemistry, respectively [54]) and where F is the Faraday constant. Similarly, at least for cases where the reactive hydrides of 1H derivatives are ultimately lost as H2, the strength

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 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

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• oxidative dimers in minor amounts has already been observed by Sharpless and co-workers in their original report on CuAAC reactions [4] and was systematically investigated by Burgess et al. [56] who found that the base plays a crucial role during the formation of this type of bistriazoles. This dimerization

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• and mitigates geminate recombination and, in principle, if there is no proceeding chemical step, the product can be re-reduced if an appropriate reducing agent or potential is applied. A reversible electron transfer followed by a fast chemical step, such as dimerization of oxidized dithiolates to

• NADH-analogues are the subject of most studies for recycling sacrificial donors. NADH has been electrochemically recycled but a careful control of pH is required to prevent dimerization reactions [44][45]. For example, Glusac and co-workers recycled BIH and acridine analogues using platinum electrodes

• electrochemically irreversible oxidation or an EC mechanism where the oxidized donor undergoes a chemical step that prevents recombination but forms a stable, recyclable byproduct. The dimerization of thiolates to disulfides is a good example because unlike dimers of NADH analogues that form carbon–carbon bonds the

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

• , where the byproducts typically associated with free carbene formation (e.g., dimerization or rearrangement) were not observed (Scheme 2). In 1988, Hadjiarapoglou was investigating transition metal- and photocatalyzed intermolecular cyclopropanations between ylide 8 and norbornene, and found indane 9 was

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

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

•  7b) [31]. In 2018, Ishihara and co-workers developed a novel C2 and C1-symmetric bisphosphoric acid-catalyzed asymmetric aza-Friedel–Crafts reaction. Both catalysts showed intramolecular H-bonding causing a sharp increase in Brønsted acidity of free OH groups and prevention of catalyst dimerization

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• rotation rate of the threads by a light-driven exchange between geometric isomers of a rotaxane scaffold; and (ii) a macroscopic bending of the crystalline array by a photo-triggered dimerization reaction of two identical linear components within the macrocyclic counterpart. Thus, in all the discussed

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

• employed as effective substrates for catalytic cross-dimerization reactions. The reaction was performed in the presence of [RhCl(cod)]2 (3 mol %), taking PPh3 or (4-ClC3H4)3P as the ligand at 160 °C, for about 48 h (Scheme 39). This work provides an effective way for preparing C–H-alkenylated bipyridines

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

• [25] that ethyl 2-bromo-2'-nitrobenzoylacetate reacts with thiobenzamide to give not only the expected 4-(2-nitrophenyl)-2-phenylthiazole-5-carboxylate, but also the dimerization product of thiobenzamide – i.e., 3,5-diphenyl-1,2,4-thiadiazole (XV). Similar observations have been made with other

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• hexaphenylbenzene 68 in an 85% yield. Then the Scholl cyclodehydrogenation of compound 68 was carried out in DDQ/TfOH to afford NG 69 in a 64% yield. By the selective dimerization of azopine-containing, HBC-monomer 69, the novel BINOL-like, atropisomeric chiral oxa-nanographene 70 was obtained in high yield

• . Meanwhile, this NG 70 can also be synthesized from compound 68 through oxidative cyclodehydrognation and dimerization in one pot. The isomerization barrier was determined as over 35 kcal/mol at 170 °C, and 37 kcal/mol by DFT calculation, indicating a high degree of optical stability of pure enantiomers [51

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• two 7-(arylethynyl)-1,8-bis(dimethylamino)naphthalene fragments was prepared via the Glaser–Hay oxidative dimerization of 2-ethynyl-7-(arylethynyl)-1,8-bis(dimethylamino)naphthalenes. The oligomers synthesized in this way are cross-conjugated systems, in which two conjugation pathways are possible: π

• oligomers 5 can be synthesized by a Glaser oxidative dimerization of monomers 6 (Scheme 1). The obvious route for the synthesis of the latter is the sequential alkynylation of 2,7-diiodonaphthalene 8. In accordance with this strategy, diiodide 8 was cross-coupled with copper(I) arylacetylides (Castro

• recrystallization of the crude product from ethanol. Next, the oxidative dimerization of terminal alkynes 6a–e was carried out in an aerobic medium in the CuI/TMEDA/iPr2NH system at room temperature, which proved to be effective in the synthesis of butadiynes 1–4 [15] (Scheme 3). The desired diarylbutadiynes 5a–e

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• )-1-benzylpyrrolidine-2-carboxamide) and its Ni(II)–Schiff base complexes formed of glycine, serine, and dehydroalanine are reported. A bulky tert-butyl substituent in the phenylene fragment precludes unwanted oxidative dimerization of the Schiff base complex, making it suitable for targeted

• dimerization of the Schiff base complex and the radical cation formed under one-electron electrochemical oxidation will be sufficiently stable, opening a route to further oxidative modification of the amino acid side chain under appropriate conditions. Additionally, this bulky group may significantly alter the

• be shown below, this is not necessary since the isomeric Schiff base template proved efficient in stereoselective modification of amino acids. The products of the oxidative dimerization via the phenylene ring were not detected for both isomeric templates. The subsequent reaction with (S

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• equiv) in PhMe led to the corresponding macrolide 28 in 20% yield. Since the demethylation step of 28 was known [27], the authors described a formal synthesis of combretastatin D-2 (2, Scheme 6). Despite the low yield, the authors managed to bypass the dimerization reaction previously reported by Boger

• conditions for the metathesis using the 1st generation Grubbs catalyst were attempted without success, but when 2nd generation catalyst was used, the dimerization product 100 was observed (Scheme 20). Despite the yield for macrolide formation, Cousin proposed alternatives for the formal synthesis of 2

• catalysts, through dimerization of a single molecule. Pettit and co-workers investigated the influence of structural modifications on the biological activity of combretastatins D-2 (2) and D-4 (4). The authors also investigated the influence of solvents and functional groups in the total synthesis of the

An accelerated Rauhut–Currier dimerization enabled the synthesis of (±)-incarvilleatone and anticancer studies

• Tharun K. Kotammagari,
• Sweta Misra,
• Sayantan Paul,
• Sunita Kunte,
• Rajesh G. Gonnade,
• Manas K. Santra and
• Asish K. Bhattacharya

Beilstein J. Org. Chem. 2023, 19, 204–211, doi:10.3762/bjoc.19.19

• The total synthesis of racemic incarvilleatone has been achieved by utilizing unexplored accelerated Rauhut–Currier (RC) dimerization. The other key steps of the synthesis are oxa-Michael and aldol reactions in a tandem sequence. Racemic incarvilleatone was separated by chiral HPLC and the

• nonetheless, they exhibited very limited growth suppression activity. Keywords: dimerization; incarviditone; incarvilleatone; oxa-Michael; Rauhut–Currier; Introduction (±)-Incarvilleatone (1) is a dimeric cyclohexylethanoid isolated by Zhang and co-workers [1] in racemic form from the Chinese plant

• displayed cytotoxicity against the HL-60 cell line with an IC50 value of 14.8 mg/mL and against the 6T-CEM cell line with an IC50 value of 22.2 mg/mL. Lawrence et al. [3] and Tang et al. [4] have reported the synthesis of (±)-incarvilleatone (1) and (±)-incarviditone (2) via biomimetic dimerization of

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• the total synthesis of (−)-psychotriasine (202), (−)-calycanthidine (203), and (−)-chimonanthine (204). Synthesis of structurally diverse lignans (Zhu, 2022) [103]: Lignans are structurally diverse natural compounds generated biosynthetically by the oxidative dimerization of phenylpropanoids [104