Generation of Silicon-Centered Stereogenicity by Chiral Counteranion-Directed Desymmetrization of Silanediols

Abstract

An enantiotopic group-selective monosilylation of silanediols using List’s counteranion-directed silylation methodology is reported. A silylium-ion-like silicon electrophile generated from an allylic silane paired with an imidodiphosphorimidate (IDPi) enables the enantioselective discrimination of the two hydroxy groups attached to the prochiral silicon atom. The enantioselectivity achieved in the desymmetrization step is further improved by a subsequent kinetic resolution to arrive at silicon-stereogenic disiloxanes with high enantiocontrol, along with minor amounts of the achiral trisiloxane byproduct.