Aldol/Brook/Carbon Skeletal Rearrangement Cascade Reactions of β‐Silyl Ketones with Aldehydes

Abstract

Abstractβ‐Silyl ketones reacted with aldehydes by treatment with KMMDS in the presence of 18‐crown‐6 to give β,γ‐unsaturated ketones accompanied with a skeletal rearrangement. The reactions proceeded by aldol reaction of β‐silyl ketones with aldehydes followed by [1,4]‐Brook rearrangement and intramolecular 1,2‐addition to form cyclopropanol derivatives, in which carbon‐carbon bond cleavage took place to afford β,γ‐unsaturated ketones. The β,γ‐unsaturated ketones were prepared in a one‐pot manner by conjugate addition of silyl anions to α,β‐unsaturated ketones followed by reactions with aldehydes. The Brook rearrangement proceeded with complete inversion of configuration at the carbon center.