Three-Component Coupling Reactions of Silylglyoxylates,Alkynes,and Aldehydes:A Chemoselective One-Step Glycolate Aldol Construction

摘要

Multicomponent coupling reactions can effect sequential bond constructions and rapidly increase molecular complexity in a single synthetic operation.In this context,acylsilanes1 have found broad utility as reagents that act as a center of reactivity for both nucleo-philes and electrophiles by virtue of a [l,2]-Brook rearrangement.Metallocyanide and metallophosphite nucleophiles reveal latent (silyloxy)carbanions of acylsilanes following a nucleophilic addi-tion/[l,2]-Brook rearrangement sequence (Scheme 1).Because silyl migration is facilitated by the stabilization of the nascent anion by the nitrile or phosphonate groups,one might conjecture that extant electron-withdrawing functionality in the acylsilane moiety may also promote silyl migration.For this reason Silylglyoxylates (1),a class of acylsilanes that possess an embedded anion stabilizing group,captured our attention.Herein we report three-component coupling reactions of Silylglyoxylates (1),terminal alkynes,and aldehydes to furnish glycolate aldols that bear two contiguous stereocenters (eq 1,Table 1).