Article
Chemistry, Organic
Hiroki Murakami, Ayano Yamada, Kenichi Michigami, Yoshiji Takemoto
Summary: A novel method has been developed in this study for controlling carbonyl alpha-chirality and functionalizing beta-position through the conjugate addition-asymmetric protonation (CAAP) of alpha,beta-unsaturated carboxylic acids using chiral thiourea-amino boronic acid hybrid catalysts. This method is also applied in the asymmetric synthesis of biologically active compounds.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Dongmin Kwak, Sehwa Jung, Hyeonbin Ha, Taedong Han, Do Hyun Ryu, Hyunwoo Kim, Jaesung Kwak
Summary: We present efficient synthetic methods for 1,2-aminoalcohols via electroreductive coupling between N-acyl diarylketimines and aldehydes. Mechanistic studies suggest that the reaction is initiated by selective electrochemical single electron transfer (SET) of N-acylketimines. The developed electrochemical protocol is compatible with biorelevant functional groups, allowing late-stage functionalization of pharmacophores.
Article
Chemistry, Applied
Fushuai Li, Zhihong Yang, Yanyan Yang, Qiuhong Huang, Xuling Chen, Pengfei Li, Mingxin Dong, Wenjun Li
Summary: A chiral phosphorus acid catalyzed enantioselective 1,4-conjugate addition of arylamines to in situ formed 7-methylene-7H-indoles from 7-indolylmethanols has been successfully developed for the first time without the use of additives. The catalytic protocol enables the formation of 1,4-adducts with a nitrogen-containing tertiary carbon stereocenter in moderate to high yields and good enantioselectivity under mild reaction conditions.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Review
Chemistry, Applied
Yong-Xing Song, Da-Ming Du
Summary: The aza-Michael addition cascade reaction is an important synthetic method for constructing functionalized C-N bonds, widely used in the synthesis of chiral drugs, intermediates, and natural products. This review highlights recent developments in asymmetric synthesis, including various types of aza-Michael addition triggered cascade reactions, reaction mechanisms, and derivatization experiments.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Tianyi Zhang, Yuji Nishiura, Alexander Q. Cusumano, Brian M. Stoltz
Summary: A general method for the asymmetric conjugate addition of arylboronic acids to beta-alkyl/aryl alpha,beta-unsaturated lactams has been reported, which enables the high-yielding and enantioselective synthesis of chiral beta,beta-disubstituted lactams.
Article
Chemistry, Organic
Jihoon Jang, Dae Young Kim
Summary: The electrochemical N-centered radical addition/semipinacol rearrangement sequence of alkenyl cyclobutanols with sulfonimides is a green and efficient method that avoids the use of stoichiometric amounts of external redox reagents. β-amino cyclic ketone derivatives can be synthesized in moderate to high yields under mild constant current electrolysis conditions.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
C. S. Athira, D. Basavaraja, Praveen K. Valmiki, D. Shridevi, Sasidhar B. Somappa
Summary: A simple and efficient method for the synthesis of 2-aryl-3-acylquinolines has been described, which involves cascade reactions including oxidation, addition, and condensation. The reaction achieved good yields under specific conditions and further diversification was achieved through functionalization.
TETRAHEDRON LETTERS
(2022)
Article
Biochemistry & Molecular Biology
Mingliang Zhang, Pin Zhao, Qilv Liu, Xinlei Liu, Jingya Hu, Dongqing Wu, Lantao Liu
Summary: A catalyst-free tandem reaction for the construction of C(sp(3))-O bonds through aza-Michael addition and C(sp(3))-O bond formation was developed. Substituted amino ferrocenes reacted with quinone esters to produce N-ferrocene-substituted benzodihydrooxazoles in moderate to excellent yields (up to >99% yield). The quinone esters acted as both substrate and oxidant in this transformation. Key features of this method include good functional group tolerance, broad substrate scope, and mild reaction conditions.
Article
Chemistry, Multidisciplinary
Kiran Kumari, Meeta Bhati, Roopendra Singh Madhukar, Akram Gulam Hussain Khan, Prachi Janjani, S. Rajagopala Reddy, Srinivasan Easwar
Summary: A sulfonamide moiety was introduced at the C-4 position of proline, cis to the -COOH group, to investigate a possible synergistic interaction between the two functional groups and its consequent influence on the enamine mediated asymmetric aldol reaction. The results demonstrate that the resulting catalyst is capable of efficiently producing aldol adducts with excellent diastereo- and enantioselectivities in the presence of water.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Kiran Kumari, Meeta Bhati, Roopendra Singh Madhukar, Akram Gulam Hussain Khan, Prachi Janjani, S. Rajagopala Reddy, Srinivasan Easwar
Summary: A sulfonamide moiety was introduced at the C-4 position of proline, cis to the -COOH group, to investigate the potential synergistic interaction between the two functional groups and its influence on the enamine mediated asymmetric aldol reaction. The resulting catalyst exhibited high efficiency in producing aldol adducts with excellent diastereo- and enantioselectivities in the presence of water. Computational study was also conducted to gain further insights into the proposed cooperative assistance.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Subhash P. Chavan, Dinesh B. Kalbhor, Rajesh G. Gonnade
Summary: A synthesis of 2-epi-biotin sulfone was achieved from commercially available L-cysteine, involving a tandem S,N-carbonyl migration/aza-Michael/spirocyclization reaction and a late-stage Haller-Bauer reaction for diastereoselective carbon side chain introduction.
Article
Chemistry, Physical
Viktoria Kozma, Zsolt Szakonyi, Gyorgy Szollosi
Summary: This study reveals the structural effects of beta-amino acids on the asymmetric Michael additions, including the impact of substituent bulkiness on selectivity, the beneficial arrangement of functional groups in cis isomers, and the influence of nitrogen substituents on reaction rate and enantioselectivity.
Article
Chemistry, Organic
Si-Qi Xiong, Chuan-Ming Hong, Qing-Hua Li, Tang -Lin Liu
Summary: A non-noble Cu-catalyzed transfer aza-benzyl Michael addition via the C-C bond cleavage of aza-benzyl alcohols has been reported. The unstrained C(sp(3))-C(sp(3)) bond of the alcohol is selectively cleaved. This aza-benzyl transfer strategy allows for selective and environmentally friendly C-alkylation of a,beta-unsaturated carbonyl compounds using readily available alcohols as carbon nucleophiles, and it exhibits a wide substrate scope and high yields.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Fangfang Guo, Jiean Chen, Yong Huang
Summary: Recently, chiral N-heterocyclic carbenes (NHCs) have been established as powerful catalysts for enantioselective bond-forming processes via noncovalent interactions. A bifunctional NHC with an embedded hydrogen-bonding motif has been reported in this study, showing remarkable tolerance of various Michael acceptors in an asymmetric aza-conjugate addition reaction, with catalytic efficiency far exceeding that of the benchmark tertiary amine-thiourea scaffold.
Article
Chemistry, Applied
Andrea Guerrero-Corella, Miguel A. Valle-Amores, Alberto Fraile, Jose Aleman
Summary: An asymmetric organocatalytic aza-Michael addition reaction of ketimines to nitroolefins is described, utilizing 2-hydroxybenzophenone imine to improve the enantioselective addition of N-centered nucleophiles to nitroalkenes. The versatility of the process is demonstrated under both batch and flow conditions, resulting in the synthesis of a wide variety of nitroamine derivatives with excellent yields and enantioselectivities. Additionally, this methodology was successfully applied to the formal synthesis of VNI, a drug-like scaffold for the treatment of Chagas disease.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Keshaba N. Parida, Gulab K. Pathe, Shimon Maksymenko, Alex M. Szpilman
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2018)
Article
Chemistry, Inorganic & Nuclear
Abhaya K. Mishra, Galit Parvari, Irit Cohen, Natalia Fridman, Yoav Eichen, Alex M. Szpilman
JOURNAL OF COORDINATION CHEMISTRY
(2018)
Article
Multidisciplinary Sciences
Shlomy Arava, Shimon Maksymenko, Keshaba Nanda Parida, Gulab K. Pathe, Atul M. More, Yuriy B. Lipisa, Alex M. Szpilman
JOVE-JOURNAL OF VISUALIZED EXPERIMENTS
(2018)
Article
Chemistry, Organic
Atul A. More, Sourav K. Santra, Alex M. Szpilman
Article
Chemistry, Multidisciplinary
Shlomy Arava, Sourav K. Santra, Gulab K. Pathe, Raja Kapanaiah, Alex M. Szpilman
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Organic
Atul A. More, Alex M. Szpilman
Article
Chemistry, Organic
Sourav K. Santra, Alex M. Szpilman
Summary: In this study, a visible-light-mediated benzylic C-H oxygenation reaction has been reported, which can take place at ambient temperature and air pressure with higher yield than current industrial conditions.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Abhaya K. Mishra, Galit Parvari, Sourav K. Santra, Andrii Bazylevich, Ortal Dorfman, Jonatan Rahamim, Yoav Eichen, Alex M. Szpilman
Summary: This study presents a peptide coupling reaction design that relies on sun-light activation to generate a novel coupling reagent in situ. The method is rapid, does not require dry solvents or inert atmosphere, and is compatible with all common amino acids and protecting groups. The proposed mechanism is supported by experimental and computational studies.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Chemistry, Organic
Ishita Neogi, Alex M. Szpilman
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Multidisciplinary
Sagi Sevilia, Galit Parvari, Jonathan Bernstein, Natalia Fridman, Dan Grinstein, Levi Gottlieb, Yoav Eichen, Alex M. Szpilman
Summary: We have shown that salts of 1-(2-hydroxyethyl)-1H-imidazol-3-ium and 1-(2-hydroxyethyl)-3-methyl-1H-imidazol-3-ium, as well as their nitrite ester salts, possess high decomposition enthalpies, high decomposition temperatures, and high densities. Particularly, the perchlorate salts exhibit potential as energetic materials. Many of these salts are ionic liquids, which could be useful as energetic plasticizers or gel fillers.
Article
Chemistry, Organic
Lenin Kumar Verdhi, Natalia Fridman, Alex M. Szpilman
Summary: A chiral nitroxide catalyst, generated in situ by a readily prepared chiral hydroxylamine precatalyst, in combination with a copper co-catalyst, serves as an environmentally friendly terminal oxidant for the enantioselective oxidative kinetic resolution of racemic axially chiral N-arylpyrrole alcohols, providing high enantioselectivity and reaction efficiency.
Article
Chemistry, Organic
Asit Ghosh, Yuriy B. Lipisa, Natalia Fridman, Alex M. Szpilman
Summary: 2-Nitrocyclopropanes with various functional groups can be obtained as single diastereoisomers in one step by introducing ketones, amides, esters, and carboxylic acids at the 1 position of corresponding unsaturated carbonyl compounds using nitromethane as the nitromethylene component. The reaction proceeds at room temperature under mild conditions and the products can be further transformed into cyclopropyl-amino acids, among others. Nitrocyclopropanes and aminocyclopropanes are important structural motifs found in biologically active compounds and natural products.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Lenin Kumar Verdhi, Asit Ghosh, Natalia Fridman, Alex M. Szpilman
Summary: A copper and chiral nitroxide co-catalyzed aerobic enantioselectiveoxidation process has been developed for the synthesis of axially chiral molecules. Two complementary atroposelective approaches, oxidative kinetic resolution (OKR) and desymmetrization, were studied using ambient air as the terminal oxidant. OKR results in optically pure compounds with er up to 3.5:96.5 and 5.5:94.5 for rac-N-arylpyrrole alcohols and rac-biaryl alcohols, respectively. Desymmetrization of prochiral diols produces axially chiral biaryl compounds with er up to 99:1.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Subrata Maity, Alex M. Szpilman
Summary: In this paper, a new method for the formation of 2-fluoroenones from ubiquitous enones in a single step is reported. The reaction shows high yields (63-90%) and is applicable to a wide range of aromatic and alkenyl enones. Mechanistic investigations reveal a rare umpolung Morita-Baylis-Hillman-type mechanism.
Article
Chemistry, Organic
Hila Toledo, Boris Tumanskii, Denis Sh. Sabirov, Alexander Kaushansky, Natalia Fridman, Alex M. Szpilman
ORGANIC & BIOMOLECULAR CHEMISTRY
(2019)