2023 Volume 71 Issue 7 Pages 466-484
A strategy for symmetric synthesis based on dynamic chirality of enolates (memory of chirality) has been developed. Asymmetric alkylation, conjugate addition, aldol reaction, and arylation via C–N axially chiral enolate intermediates are described. Asymmetric alkylation and conjugate addition via C–O axially chiral enolate intermediates with a half-life of racemization as short as approx. 1 s. at −78 °C have been accomplished. Organocatalysts for asymmetric acylation and site-selective acylation have been developed. Kinetic resolution of racemic alcohols via remote asymmetric induction by the catalyst is shown. Catalyst-controlled site-selective acylation of carbohydrates and its application to total synthesis of natural glycoside are described. Chemo-selective monoacylation of diols and selective acylation of secondary alcohols with reversal of inherent reactivity are also discussed. Geometry-selective acylation of tetrasubstituted alkene diols is achieved, where acylation takes place independent from the steric environments of the substrates.
