Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• cyclization (Scheme 51A) [93]. The reaction starts with the coordination of the Rh catalyst to the propargyl alcohol 198. In the presence of a base, the rhodium–alkynyl reagent is generated with the concomitant extrusion of benzophenone. Finally, the alkynylation of the enone is followed by the cyclization

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

• electrochemically induced oxidative modification of the amino acid side chain. Experimental and DFT studies showed that the additional tert-butyl group increases the dispersion interactions in the Ni coordination environment making the complexes more conformationally rigid and provides a higher level of

• base chiral template is a fairly versatile “tool” that can be adapted to a specific task. A relatively new approach to functionalization of amino acids is a combination of a stereoselective synthesis in a metal-coordination environment with electrochemical activation [31]. It increases the reactivity

• benzyl fragment was observed. This indicated that H-2 is located on the same side of the nickel coordination plane as the benzyl substituent at the proline nitrogen atom, leading to the ʟ-configuration of the α-amino acid stereocenter. Notably, the major stereoisomer of all thiolated compounds (RCysNi)L7

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• the reaction with tert-butyl-N-allyl carbamate 7g (1:6) while the reaction with allylcyclohexane resulted with the lowest yield (7f, 28%), probably due to the steric hindrance of the reagents. In the case of N-Boc-allylamine, improved diastereoselectivity might result from the coordination of the

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• -defined and rigid nature of these bicyclic alkenes creates two diastereotopic faces, namely the endo and exo face (Figure 2). The exo face is sterically less congested than the endo face; therefore, the exo face will typically interact with metal catalysts through side-on coordination of the olefin, and

• in the case of heterobicyclic alkenes, the heteroatom. This preferential exo coordination is not always the case, as norbornadiene derivatives are known to preferentially form chelated endo complexes which can change the stereochemical outcome of the reaction. Nevertheless, the predisposition of

• metal catalysts towards coordination on the exo face biases the reaction outcome towards exo-selective functionalization. Upon exo coordination of a metal catalyst with the π system and subsequent migratory insertion, the resulting alkyl metal intermediate is quite limited in how it can propagate. In

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• involved in most cases an electrophilic SCF3 source (R1R2NSCF3). For these transformations, the following working hypothesis was generally suggested (Scheme 4). After coordination of the palladium catalyst to a directing group, the metallacycle A is formed. This latter undergoes an oxidative addition in

Mechanochemical solid state synthesis of copper(I)/NHC complexes with K₃PO₄

• Ina Remy-Speckmann,
• Birte M. Zimmermann,
• Mahadeb Gorai,
• Martin Lerch and
• Johannes F. Teichert

Beilstein J. Org. Chem. 2023, 19, 440–447, doi:10.3762/bjoc.19.34

• for catalytic ester reduction with H2 [48], led to lower catalyst activity. Possible coordination of residual phosphate to the guanidine moiety was excluded as analysis by 31P NMR experiments. The copper(I)-catalyzed 1,2-reduction of functionalized ester 10 was also successfully achieved using the

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• suggested a weak intramolecular inter-porphyrin communication. Further investigation also revealed that the interaction of the star compound 129 with DABCO and Bipy possibly led to the double star formed by the axial coordination of ligand with zinc centers. The synthesis of supramolecular nanoassemblies

• porphyrin groups were observed in nonpolar solvents. In addition, UV–vis and fluorescence spectra also showed that the 1,2,3-triazole moiety can stabilize zinc porphyrin by forming an intermolecular coordination complex. Also, it was found that porphyrin complex 160 is easy to synthesize, is fat soluble and

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• . Next, the iodonium center was stabilized through an additional N-coordination via ortho-pyrazole substitution, giving the iodonium salts 5ba and 5bb in 88% and 50% yield. When replacing imidazoles by indazoles the oxidation was not as efficient giving the products 5bc and 5bd with only 24% and 44

• indazole salt 5be was isolated in 30% yield and the benzyl-bridged, seven-membered salt 5bf could not be obtained under our optimized reaction conditions. Single crystal structures of selected salts were obtained to gain a better understanding of the bonding situation and the coordination states in these

• group significantly disturbs the triflate coordination to the other iodine σ-hole, which results in a C15–I1–O5 angle of 145.50°. In contrast to other six-membered iodonium salts, this molecule is nearly in plane with an I1–C1–C15–N4 dihedral angle of 2.03° [30][32]. For the dicationic salt 5av, we

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• ]. The exact nature of the interaction between the active ate-ferrous complex and the NMP-ligated magnesium cation is so far unknown. Although often neglected in the mechanistic analysis of a cross-coupling system, the importance of the coordination sphere of the main-group cation brought by the

• nucleophilic partner R[M] in a cross-coupling has been reported in the recent literature. It was indeed shown that some ligands (such as diphosphines) used in Fe-catalyzed Negishi cross-coupling reactions (R[M] = RZnX) were actually involved in the coordination of the ZnII cation in a key on-cycle

• transmetallation step, and not in the coordination of the iron-containing intermediates [36][37]. The use of magnesium alkoxide salts, either as an ω-functionalization of the nucleophilic partner (Scheme 4) or as an external molecular additive such as EtOMgCl (Scheme 5), also likely proceeds similarly to the NMP

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy

• Jiayue Fu,
• Bingbing Li,
• Zefang Zhou,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169

• the electron-donating phenyl ring enabled the coordination of the alkyne with the Au+ complex in the α-position, which promoted the silyl ether to attack the β-position of the alkyne to promote a 6-endo-dig cyclization. Next, compound 11 was subjected to a solution of tetrabutylammonium fluoride (TBAF

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

• Koustav Singha,
• Imran Habib and
• Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

• histidine and the related local-immune hormone histamine. In the structural view of DNA and RNA, purine bases contain imidazole moieties. Also, imidazole N-oxides have various and intriguing applications in natural products synthesis, catalysis, and coordination chemistry [3]. Derivatives of imidazole

An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids

• Stephen J. I. Shearan,
• Enrico Andreoli and
• Marco Taddei

Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160

• . Phosphonates can also be employed as organic linkers in combination with metal ions to afford coordination polymers and metal-organic frameworks (MOFs), or more aptly, metal phosphonate frameworks [19][20]. One of the main challenges in the synthesis of metal phosphonates is that the linkers are rarely

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• properties. Such switchable systems with conjugated organic fragments containing an FeII/FeIII system were used in organic electronics as molecular switches, optoelectronic materials and in biochemistry as photonic or redox devices [6]. A promising approach is the coordination self-assembly of multiferrocene

• phosphines, a relatively small number of trivalent phosphorus derivatives has been used to construct multiferrocene compounds. The use of ferrocene derivatives containing a phosphorus–sulfur bond is a promising direction, since coordination with a metal atom can occur both at the phosphorus and sulfur atoms

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

• Arisu Koyanagi,
• Yuki Murata,
• Shiori Hayakawa,
• Mio Matsumura and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

• study (which required no base; Table 1, entry 18), a possible mechanism for this cyclodesulfurization approach is shown in Scheme 4. The formation of intermediate A based on S···Bi [42][43] and Cl···H inter-coordination is anticipated from the reaction of thioamide 2 and Ph3BiCl2 6a as an initial step

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• governed not only by the nature and length of the side arms but also by the size and geometry of the central scaffold [2][4]. By changing the scaffold, the volume of the cavity created by the three arms can be tuned allowing for the coordination of ions and molecules of different sizes [4]. For this reason

• in an atypical +4 oxidation state [27][28][29]. Recently, TAAD was used to improve the thermal and photochemical stability of MAPbI3 perovskite films (most likely through coordination of Pb(II) ions) [30]. The disadvantages of 3O-TAADs, however, are limited thermal stability (due to cage opening to

• –178.1°) forming two -cyclic motifs. There seems to be a preference for the coordination of certain guest molecules depending on the nature of the amide/carbamate groups. Thus, N-propionyl and ethyl carbamate derivatives (4a, 4a·HCl, and 4b) form the aforementioned complexes with water (Figure 3c

Synthesis of meso-pyrrole-substituted corroles by condensation of 1,9-diformyldipyrromethanes with pyrrole

• Baris Temelli and
• Pinar Kapci

Beilstein J. Org. Chem. 2022, 18, 1403–1409, doi:10.3762/bjoc.18.145

• porphyrins, are tetrapyrrolic aromatic compounds, with the lack of one meso-carbon atom on the macrocycle [1][2][3][4]. This feature supplies a smaller ring cavity than in the case of porphyrins, three NH in the core, and coordination ability with high-valence transition metal ions. It is noteworthy that

Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase

• Sanaz Ahmadipour,
• Alice J. C. Wahart,
• Jonathan P. Dolan,
• Laura Beswick,
• Chris S. Hawes,
• Robert A. Field and
• Gavin J. Miller

Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142

• Asp260 & Asp109 in coordination with Mg2+ and two water molecules in close proximity to C6 [16]. Evaluation of GDP 6-chloro-6-deoxy-ᴅ-mannose against GMD GMD from P. aeruginosa was co-incubated with GDP-mannose 1 and sugar nucleotide 19, and the production of NADH monitored by fluorescence (excitation

Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes

• Almaz A. Zagidullin,
• Farida F. Akhmatkhanova,
• Mikhail N. Khrizanforov,
• Robert R. Fayzullin,
• Tatiana P. Gerasimova,
• Ilya A. Bezkishko and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139

• objects of growing interest in the fields of coordination chemistry [3][4][5] and asymmetric catalysis [6][7]. Due to the sp2-hybridization of the phosphorus atom, phosphaferrocenes are commonly regarded as phosphorus ligands with weaker σ-donor character than classical tertiary phosphines and stronger π

• mediator in the synthesis of asymmetric phosphines starting from white phosphorus [15]. Moreover, the presence of the lone pair of the P atom opens the route to polynuclear complexes [16][17][18] and coordination polymers [19][20][21] with the mixed σ-/π-coordination mode, which is not typical for

Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions

• Michael Keppler,
• Sandra Moser,
• Henning J. Jessen,
• Christoph Held and
• Jennifer N. Andexer

Beilstein J. Org. Chem. 2022, 18, 1278–1288, doi:10.3762/bjoc.18.134

• fractions [5][10][15][16]. Based on the crystal structures of three PPK2-III, the coordination of polyP and ADP by positively charged amino acids (lysine and arginine) has been suggested [16][17]. Two magnesium ions are held in place by two conserved aspartate residues that further coordinate the polyP and

• [33][34]. Under physiological conditions as well as in an in vitro system the actual ΔG may be different by coordination of cations and the ionic strength, temperature and pH of the reaction solution [29][35][36]. Compared to other ATP synthesis reactions very little is known about the thermodynamics

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• ) coordination environment in the form of a Schiff base is considered as a route to electrochemical broadening of the donor–acceptor cyclopropane concept in combination with chirality induction in the targeted products. A tendency to the reductive ring-opening and the follow-up reaction paths of thus formed

• construction of complex multifunctional molecules [3][4][5][6][7][8]. Recently, we elaborated a versatile electrochemical approach for the stereoselective functionalization of a side chain of amino acids involved in the Ni(II) chiral coordination environment [9][10][11][12][13][14][15]. A combination of redox

• stereoselective functionalization has not been probed as yet. Herein, reductive three-membered ring opening in the chiral α,α-cyclopropanated amino acids involved in the Ni(II)–Schiff base coordination environment is reported. Follow-up transformations of thus formed radical anions will be discussed, including

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• ). Increasing the amount of alkyne 4 increases the probability of the alkyne being coordinated in contrast to the tetrazole, which leads to launching of the CuAAC cycle. The probability of coordination on the tetrazole should also be indirectly impacted by this. However, the imidazole formation is only slightly

• -triazoloquinoxaline ligand in a distorted octahedral coordination geometry in all cases. The obtained data for the alkyl-chain complex 27a corresponds to similar published results [12]. For complex 29, single crystals were formed from slow evaporation of a methylene chloride solution under ambient conditions. The

• crystal structure confirmed that rhenium is coordinated to three carbonyl groups, the bromine atom and two nitrogens of the 1,2,3-triazoloquinoxaline ligand. However, in this case, instead of coordination via the quinoxaline nitrogen and the 2-nitrogen of the triazole ring, the complex is formed via

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• materials with the introduction of Lewis acids have been frequently observed due to either physical or chemical interactions. In this mini-review, we elaborate how Lewis acids adjust the optical properties and the bandgap of luminescent materials by simple coordination reactions. It is common that

• fluorescent materials containing Lewis basic nitrogen heterocycles are more likely to provide the feasible band gap modulation. The essence of such phenomenon originates from Lewis acid–base coordination and adducts, which highly depends on the electron-accepting property of the Lewis acids. This

• coordination between Lewis acids and bases, which can finely adjust the optoelectronic properties of the fluorescent molecules, such as band gaps, peak wavelengths, and even frontier molecular orbitals if bound together [20]. The traditional way to manipulate the optoelectronic properties of the emitters

Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

• Jamshid Amiri Moghaddam,
• Huijuan Guo,
• Karsten Willing,
• Thomas Wichard and
• Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

• tyrosine (Tyr-56) residue, which likely fulfills a similar coordinative function. Furthermore, a conserved arginine residue (UbiA-297 R145) was detectable, which was located in the neighboring α-helix (R145) and in proximity to the binding motif, and was hypothesized to be involved in the coordination

Structural basis for endoperoxide-forming oxygenases

• Takahiro Mori and
• Ikuro Abe

Beilstein J. Org. Chem. 2022, 18, 707–721, doi:10.3762/bjoc.18.71

• ) [64][65][66][67]. The Fe(II) is coordinated by the conserved 2-His-1-Asp residues and a 2OG in the active site. The binding of a substrate in the active site, where it is close to the Fe(II) center, provides a coordination site for O2. Subsequently, the oxidative decarboxylation of 2OG generates a

• bond interactions. Grey dashed lines show the coordination of the iron atom. Iron atoms are depicted by orange spheres. Structure of NvfI [28]. (A–C) Conformational changes of loop regions: (A) open conformation, (B) partially closed conformation, and (C) closed conformation of NvfI. (D) The active