Visible Light-Induced Transformation of β-Aryl-α,β-Unsaturated Acylsilanes into Indenol Derivatives via Alkenyl Siloxycarbenes

Abstract

A visible-light-driven, catalyst-free strategy for the synthesis of indenol derivatives from readily accessible β-aryl-substituted α,β-unsaturated acylsilanes is described. The method provides an operationally simple and sustainable alternative to conventional approaches that rely on transition-metal catalysis, delivering indenol frameworks that are valuable intermediates in the synthesis of structurally and biologically relevant molecules. Beyond its synthetic utility, the transformation proceeds through an unusual multistep cascade involving trans–cis isomerization, a Brook rearrangement, electrocyclization, and a terminal [1,5]-hydrogen shift. Mechanistic studies combining experimental observations with computational analysis reveal a key role for siloxycarbene intermediates and establish their participation in electrocyclization processes. These findings not only expand the reactivity landscape of acylsilane-derived intermediates but also provide new insights into photochemically driven, catalyst-free reaction design and the chemistry of oxycarbenes.