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Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
Development of asymmetric reactions catalyzed by chiral organotin-alkoxide reagents
Akira Yanagisawa1, Kazuhiro Yoshida
1Department of Chemistry, Graduate School of Science, Chiba University, Inage, Chiba 263-8522, Japan. ayanagi@faculty.chiba-u.jp
Abstract:
Asymmetric catalysis under almost-neutral reaction conditions is key for the efficient synthesis of optically active polar molecules. We have developed catalytic enantioselective reactions of acyclic or cyclic alkenyl esters by using an (S)-BINOL-derived chiral tin-dibromide reagent that possesses a bulky aryl group at the 3 or 3' position as the chiral pre-catalyst in the presence of a sodium alkoxide and an alcohol, in which a chiral tin alkoxide bromide is generated in situ and recycled with the assistance of an alcohol. In this Personal Account, we describe three types of asymmetric transformation that proceed through a chiral tin enolate: 1) The asymmetric aldol reaction of alkenyl esters or unsaturated lactones with aldehydes or isatins; 2) the asymmetric three-component Mannich-type reaction of alkenyl esters and related cycloaddition reactions; and 3) the asymmetric N-nitroso aldol reaction of unsaturated lactones with nitrosoarenes.
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