Visible-Light-Induced Catalyst-Free Carboxylation of Acylsilanes with Carbon Dioxide

Abstract

Intermolecular carbon-carbon bond formation between acylsilanes and carbon dioxide (CO₂) was achieved by photoirradiation under catalyst-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of the acylsilanes added to the C═O bond of CO₂ to give α-ketocarboxylates, which underwent hydrolysis to afford α-ketocarboxylic derivatives in good yields. Control experiments suggest that the generated siloxycarbene is likely to be from the singlet state (S₁) of the acylsilane and the addition to CO₂ is not in a concerted manner.