Acylsilanes in rhodium(III)-catalyzed directed aromatic C-H alkenylations and siloxycarbene reactions with C-C double bonds.

Acylsilanes are known to undergo a 1,2-silicon-to-oxygen migration under thermal or photochemical conditions to form siloxycarbenes. However, there are few reports regarding the application of siloxycarbenes in organic synthesis and surprisingly, their reaction with CC double or triple bonds remains virtually unexplored. To facilitate such a study, previously inaccessible aromatic acylsilanes containing an ortho-tethered CC double bond were identified as suitable substrates. To access these key intermediates, we developed a new synthetic method utilizing a rhodium-catalyzed oxidative Heck-type olefination involving the application of an acylsilane moiety as a directing group. When exposed to visible-light irradiation, the ortho-olefinated acylsilanes underwent a smooth intramolecular cyclization process to afford valuable indanone derivatives in quantitative yields. This result paves the way for the development of new transformations involving siloxycarbene intermediates.