Enantioselective isothiourea-catalysed reversible Michael addition of aryl esters to 2-benzylidene malononitriles.

ABSTRACT: Catalytic enantioselective transformations usually rely upon optimal enantioselectivity being observed in kinetically controlled reaction processes, with energy differences between diastereoisomeric transition state energies translating to stereoisomeric product ratios. Herein, stereoselectivity resulting from an unusual reversible Michael addition of an aryl ester to 2-benzylidene malononitrile electrophiles using an isothiourea as a Lewis base catalyst is demonstrated. Notably, the basicity of the aryloxide component and reactivity of the isothiourea Lewis base both affect the observed product selectivity, with control studies and crossover experiments indicating the feasibility of a constructive reversible Michael addition from the desired product. When this reversible addition is coupl

SUBMITTER: Nimmo AJ 

PROVIDER: S-EPMC10337745 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature