Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• carried out with different substituted propiolic acids 9 and DAS 1 are shown in Scheme 3. It can be noted that in the case of arylpropiolic acids, no significant influence of electronic effects of substituents in the aromatic ring was observed. In the case of the o-chloro derivative 2d the yield was

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

• sulfur extrusion [44]. It appeared that thiepines carrying sterically demanding substituents on the sulfur α-positions as well as annelated analogues show substantially increased lifetimes, owing to steric and electronic effects [45]. With these criteria in mind, a variety of thermally-stable annelated

Synthesis of spiropyridazine-benzosultams by the [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes

• Wenqing Hao,
• Long Wang,
• Jinlei Zhang,
• Dawei Teng and
• Guorui Cao

Beilstein J. Org. Chem. 2024, 20, 280–286, doi:10.3762/bjoc.20.29

• spiropyridazine-benzosultams. The electronic effects of substituents and the influence of steric hindrance on the reaction were explored. The configuration of the product was determined by X-ray single crystal diffraction. This method has the advantages of mild reaction conditions, wide substrate scope, and high

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

• of H-bonded associates (Figure 2) [20][21][22]. As discussed above, the benzene rings play only a minor role in the formation of the color of indigo and its derivatives. However, electronic effects and especially the position of the substituents in the benzene rings have pronounced influence on the

• the electron density on the N atom in the ground state due to the electronic effects of substituents facilitates charge transfer during excitation, which leads to a decrease in the energy of the transition and a bathochromic shift of the absorption band, and vice versa. Photochemistry of indigo

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

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

• ) with activation free energies 47 and 59 kJ·mol−1 than from 4-bromo-1,1-dimethyl-1,4-dihydroisoquinolin-3(2H)-one (2b) and N-phenyl-2-bromo(phenyl)acetamide (4a) with activation free energies 78 and 88 kJ·mol−1. These trends fully correspond to a combination of electronic effects (bridging C=O has an

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• us [51] in order to investigate the reaction optimization by HPLC-UV. After that, the reactant scope of the reaction was explored by involving to the reaction APBTTs 1a–h, bearing various aroyl substituents, and arylamines 11a–d, bearing aryl substituents with various electronic effects (Scheme 18

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• catalyst shows the increase in selectivity compared to the reaction catalyzed by NHPI. In principle, the regioselectivity of a CH-functionalization can also be controlled by electronic effects of substituents in an N-oxyl radical, which influence the O–H bond-dissociation energy in the N-hydroxy compound

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• . may influence the regioselectivity of the ferrocenoylation reaction. While the N9-position of the purine ring is a typical site of substitution, the N7-position may be preferred in some situations. In any case, the interplay between steric and electronic effects of selected substituents is crucial to

• group. In case when the steric effect is negligible (e.g., H atom at the C6-position), the N9-isomer is a minor product (less than 30%), and the acylation of the N7 position is strongly favored. In the parent purine, therefore, the nucleophilic attack is mostly controlled by electronic effects, i.e

Lewis acid-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence to access phosphoric esters

• Jin Yang,
• Dang-Wei Qian and
• Shang-Dong Yang

Beilstein J. Org. Chem. 2022, 18, 1188–1194, doi:10.3762/bjoc.18.123

• either the 3-, 4-, or 5- position of the α-pyridinealdehyde, and the desired products 3ba–bc were obtained in 32%, 92%, and 82%, respectively, indicating that the reaction is sensitive to steric effects. We then investigated the electronic effects of the α-pyridinealdehyde on the reaction outcome

• . However, no clear trend regarding electronic effects could be observed since α-pyridinealdehydes bearing either an electron-donating group (e.g., Me, MeO, Ph) or electron-withdrawing group (e.g., F, Cl, Br, CF3, CO2Me) in position 5 were all well tolerated, and the desired products were generally obtained

First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation

• Maxime Pypec,
• Laurent Jouffret,
• Claude Taillefumier and
• Olivier Roy

Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85

• are now focused on introducing chirality, which will provide a better understanding of their structural properties, including their potential to form PPII-like helices. (A) Summary of the main side chains exerting significant steric and/or electronic effects and influencing the amide conformation of

Synthesis of bis-spirocyclic derivatives of 3-azabicyclo[3.1.0]hexane via cyclopropene cycloadditions to the stable azomethine ylide derived from Ruhemann's purple

• Alexander S. Filatov,
• Olesya V. Khoroshilova,
• Anna G. Larina,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2022, 18, 769–780, doi:10.3762/bjoc.18.77

• -ene (2l) [30] reacted with ylide 1 in THF at reflux (Scheme 5). The inactivity of substrate 2k appears to be caused by electronic effects while the tetrasubstituted cyclopropene 2l seems to be too bulky to undergo a cycloaddition reaction with 1. To the best of our knowledge, PRP (1) is one of the few

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• outcome, although electronic effects can be considered to play a role, especially with substituted α-amino acids. Lanfranchi and co-workers also studied the menadione (10) alkylation by oxidative decarboxylation using carboxylic acids containing nitrogenous heterocycles as substituents, and achieved very

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• , and factors like steric and electronic effects of the nucleophile and substrate and the polarity of the solvent would influence the product ratio [75]. Here, as illustrated above, the authors introduced the cage host J as the noncovalent protecting group of the internal reactive sites, which directed

Me₃Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines

• Krishna M. S. Adusumalli,
• Lakshmi N. S. Konidena,
• Hima B. Gandham,
• Krishnaiah Kumari,
• Krishna R. Valluru,
• Satya K. R. Nidasanametla,
• Venkateswara R. Battula and
• Hari K. Namballa

Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186

• the substrate scope of this protocol. Initially, 2-(2-oxo-2-phenylethyl)benzonitrile (3a) was treated with various anilines under the optimized reaction conditions (Scheme 2). The yields of the reactions were not influenced significantly by the electronic effects of the substituents. However, the

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• both 10e and 10b starting from amine 15b2. The same trend concerning relative yields between regioisomers can be observed for fluorenones bearing the electron-withdrawing trifluoromethyl group in the same positions (see 10g, 10h, 10i1, and 10i2). This is rather surprising, as electronic effects exerted

• ). Electronic effects propagated by substituents were observed to have an influence on the reaction. In general, electron-withdrawing groups on the radical accepting arene had adverse effects, while electron donating groups, depending on the substitution pattern, had either a positive or negative effect of

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• , and the cyclization time was the same as for the 4-methoxyphenyl system 15g (Table 2, entry 10 vs 7). The outcome was more complex with ortho-substituents on the aromatic ring, since both steric and electronic effects are likely to operate. When chemically labile groups are present, decomposition of

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• were not significantly affected by the aryl substituent. Electronic effects of the alkyl group were, as expected, very weak and no significant additional distortions arise from a para- or ortho-ethyl group for products 4e and 4g. Therefore, they gave the same absorption and emission as the parent

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• -workers reported a one-pot synthesis of substituted anthracenes 37 from o-tolualdehyde 34 and aryl iodides 35 via a palladium-catalyzed C–H arylation with a silver oxidant (Scheme 8) [42]. During optimization studies, the authors noted that steric and electronic effects strongly affected the cyclization

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution

• Ryan M. Alam and
• John J. Keating

Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127

• observed > 99% N-1 regioselectivity for 3-carboxymethyl, 3-tert-butyl, 3-COMe, and 3-carboxamide indazoles. Further extension of this optimized (NaH in THF) protocol to various C-3, -4, -5, -6, and -7 substituted indazoles has highlighted the impact of steric and electronic effects on N-1/N-2 regioisomeric

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• them in view of their great significance in organic synthesis. In 2018, Miyake and colleagues [50] found a protocol for the preparation of (Z)-2-iodovinyl phenyl ether 168 by utilizing ethynylbenziodoxol(on)e (EBX) 167 and phenol derivative 166 (Scheme 59). Due to the lack of significant electronic

• effects of phenol, a variety of phenols, including electron-donor and electron-withdrawing groups, were been converted into corresponding 2-iodovinyl phenyl ethers in moderate to excellent yield with high regio- and stereoselectivities. According to the analysis of the mechanism (Scheme 60), a molecule of

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• by nucleophiles. As is the case for the nucleophilic opening of epoxides, the regiochemistry of this process is often controlled very effectively by the combined steric and electronic effects of the substituents attached to the ring, with a spectrum of SN1 and SN2-like reactivity possible. Several

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• influenced by the electronic effects induced by the substituents of the aniline unit (Table 1). Detailed information about characterization data for compounds 2a–l is given in Supporting Information File 1. X-ray crystallographic data In order to bring evidence of the geometry and arrangement of the

Efficient [(NHC)Au(NTf₂)]-catalyzed hydrohydrazidation of terminal and internal alkynes

• Maximillian Heidrich and
• Herbert Plenio

Beilstein J. Org. Chem. 2020, 16, 2080–2086, doi:10.3762/bjoc.16.175

• , 2,4,6-triisopropylphenylacetylene, and para-substituted 4-R-phenylacetylenes (R = NMe2, OMe, CF3)) with electronically variable benzohydrazides (4-R = NMe2, H, NO2) were tested, to cover a range of steric and electronic effects. Most hydrohydrazidation reactions showed nearly quantitative product