A General Route to Silacyclohexanones via Regioselective Copper-Catalyzed Borylative Cyclization

The reaction proceeds via an <i>endo</i>-selective cyclization to deliver 4-silacyclohexyl boronates, which undergo a two-step oxidation sequence to afford 4-silacyclohexanones. DFT calculations corroborate the observed selectivity, highlighting the conformational role of the silicon center in favoring the six-membered rings.

This protocol features readily available starting materials, a broad substrate scope, good functional group tolerance, and gram-scale capability. The synthetic utility of the resulting silacyclohexanones is demonstrated through diverse transformations, including ketalization, allylation, Wittig olefination, and Baeyer–Villiger oxidation.