[1,4]‐S‐ to O‐Silyl Migration: Multicomponent Synthesis of α‐Thioketones Through Chemoselective Transformation of Esters to Ketones with Organolithium Reagents.

A [1,4]-S- to O-silyl migration has been exploited to chemoselectively transform esters into ketones by using organolithium reagents, allowing multicomponent synthesis of α-thioketones. Mechanistic studies reveal that this migration proceeds in an intramolecular manner and is more favorable than the corresponding [1,5]-S- to O- and [1,3]-C- to O-silyl migrations. The resulting α-thioketones are valuable building blocks for the synthesis of cyclic or multifunctionalized organosulfur compounds.