Article
Chemistry, Applied
Eugenia Marques-Lopez, Isaac G. Sonsona, Miryam Garces-Marin, M. Concepcion Gimeno, Raquel P. Herrera
Summary: In this study, the potential of phosphites as nucleophiles for the asymmetric synthesis of chiral chromene derivatives was explored. By employing asymmetric organocatalyzed phospha-Michael addition, chiral chromenylphosphonates were synthesized using a bifunctional squaramide. The optimized protocol provided good reactivity with yields of up to 95% and chiral products with an enantiomeric excess of up to 98%.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
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, Applied
Irma Garcia-Monzon, Jorge Borges-Gonzalez, Tomas Martin
Summary: The heterogenization of homogeneous catalysts onto a solid support is a crucial step towards sustainable chemistry. In this study, we developed a series of polymer-supported tetrahydropyran-based hybrid dipeptides as active catalysts for the enantioselective Michael addition of aldehydes to beta-nitrostyrenes. The optimal anchor position and orientation between the catalyst and solid support, as well as the linker length, were carefully designed to enhance the catalytic efficiency. These supported catalysts exhibited high yields and enantiomeric excesses, and detailed deactivation studies provided important insights for prolonging their useful life.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Applied
Laura A. Bryant, Kenneth Shankland, Hannah E. Straker, Callum D. Johnston, Nicholas R. Lees, Alexander J. A. Cobb
Summary: The article describes a rare organocatalytic intramolecular cyclization of resorcinols with a high enantioselectivity using a specific organocatalyst. The obtained bicyclic resorcinols show excellent utility in the synthesis of cannabinoid-like compounds, and exhibit anticonvulsant activity.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Bence S. Nagy, Patricia Llanes, Miquel A. Pericas, C. Oliver Kappe, Sandor B. Otvos
Summary: A novel approach for enantioselective flow synthesis of rolipram has been reported, which shows significantly improved productivity compared with earlier methodologies.
Article
Chemistry, Multidisciplinary
Will C. Hartley, Florian Schiel, Elena Ermini, Paolo Melchiorre
Summary: We reported a catalytic asymmetric protocol for preparing chiral pyrrolidinones via a radical pathway. This chemistry combines photoredox catalysis and Lewis base catalysis to achieve the first example of asymmetric radical conjugate addition to alpha,beta-unsaturated anhydrides and esters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Xiu-Ning Hu, Dong-Ping Wu, Ye-Peng Xu, Pei-Qiang Huang
Summary: The first organocatalytic asymmetric synthesis of an advanced intermediate of (+)-sarain A was achieved by combining organocatalytic asymmetric Michael addition reaction and a nitrogen-to-carbon chirality transfer. This method allows for the construction of three chiral centers and chemoselective reduction of a key lactam intermediate, providing a tricyclic intermediate with all necessary functionalities for further elaboration into (+)-sarain A.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Biochemistry & Molecular Biology
Xiao-Yan Dong, Da-Ming Du
Summary: This paper investigated the organocatalytic asymmetric 1,4-Michael addition reaction of azadienes and alpha-thiocyanoindanones, successfully synthesizing a series of chiral thiocyano compounds. By describing a possible reaction mechanism, it broadens the scope of application of azadiene substrates.
Article
Chemistry, Physical
Yusuke Tokuhiro, Kosuke Yoshikawa, Sei Murayama, Takeshi Nanjo, Yoshiji Takemoto
Summary: This article presents an alternative practical method for the asymmetric synthesis of beta-amino-alpha-ketoacid equivalents, utilizing a highly stereoselective organocatalyzed Mannich-type addition using glyoxylate cyanohydrin. The optimal aminothiourea catalyst provides a variety of adducts with excellent yield and stereoselectivity, and the reaction can be applied to a wider range of imine precursors. Experimental and computational studies reveal the factors contributing to the high diastereoselectivity and enantioselectivity of the reaction.
Article
Chemistry, Multidisciplinary
Maria Sanchez-Rosello, Marcos Escolano, Daniel Gavina, Carlos del Pozo
Summary: The asymmetric intramolecular aza-Michael reaction (IMAMR) is a convenient strategy for generating heterocycles with nitrogen-substituted stereocenters, finding widespread applications in the total synthesis of alkaloids and biologically relevant compounds. Recent developments in asymmetric versions of IMAMR mainly involve the use of organocatalysts, such as chiral imidazolidinones and diaryl prolinol derivatives. The use of N-sulfinyl imines with dual roles has also emerged as a versatile mode for performing the asymmetric IMAMR.
Review
Chemistry, Multidisciplinary
Cheng Niu, Da-Ming Du
Summary: This review highlights the recent advancements in sulfa-Michael addition-triggered cascade reactions for the stereoselective synthesis of sulfur-containing compounds. It discusses various types of reactions, including sulfa-Michael/aldol, sulfa-Michael/Henry, sulfa-Michael/Michael, sulfa-Michael/Mannich and some sulfa-Michael triggered multi-step processes. The review also introduces reaction mechanisms and derivatization experiments.
Review
Biochemistry & Molecular Biology
Jianlin Han, Jorge Escorihuela, Santos Fustero, Aitor Landa, Vadim A. Soloshonok, Alexander Sorochinsky
Summary: This review critically discusses the literature data on the preparation of substituted GABA derivatives using the Michael addition reaction. Special attention is paid to asymmetric methods featuring synthetically useful stereochemical outcomes and operational simplicity.
Review
Chemistry, Organic
Barnali Jana, Monotosh Mondal, Shibashis Halder, Atanu Mahata, Sameer Saurav, Sushovan Paladhi
Summary: This article summarizes the progress made in the past 10 years in using unprotected and protected maleimides for asymmetric organocatalytic 1,4-conjugate additions. The review provides an overview of different types of nucleophiles, catalysts, substrate scope, limitations, mechanism, and synthetic utilities for each reaction. It encourages researchers worldwide to focus on the development of new methodologies, including asymmetric photo redox catalysis, for the further functionalization of maleimides.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Mariola Zielinska-Blajet, Joanna Najdek
Summary: An efficient approach to synthesizing chiral selenoureas derived from Cinchona alkaloid scaffolds was described in this study. These selenoureas were evaluated as bifunctional organocatalysts in asymmetric Michael addition reactions, with the best results achieved by those containing the 4-fluorophenyl group, showing enantioselectivities up to 96% ee. Additionally, the catalytic performance of thiourea and selenourea counterparts was compared.
Article
Chemistry, Multidisciplinary
Riccardo Conti, Anna Widera, Georgina Mueller, Csilla Fekete, Debora Thoeny, Frederik Eiler, Zoltan Benko, Hansjoerg Gruetzmacher
Summary: A simple and highly atom economic method has been found for preparing a wide range of photoinitiators adapted to specific fields of application. This method involves the addition of bis(mesitoyl)phosphine to activated carbon-carbon double bonds, using basic potassium or caesium salts as additives. Simple amine bases can also be used as catalysts, with tetramethylguanidine being a particularly outstanding catalyst.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)