Reversal of enantioselectivity in cobalt(ii)-catalyzed asymmetric Michael–alkylation reactions: synthesis of spiro-cyclopropane-oxindoles

Abstract

Herein, an asymmetric Michael–alkylation reaction with a reversal of enantioselectivity catalyzed by chiral cobalt complexes is reported. Using 2.5 mol% of Co(acac)2-imidazolidine-pyrroloimidazolone pyridine as catalyst, Michael–alkylation reaction between 3-chloro-oxindoles and...