Base-catalyzed regioselective C(sp³)-Si bond activation of silacyclobutanes and benzosilacyclobutenes.

Abstract

The development of a green, sustainable, and environment-friendly activation model is of great significance in catalytic chemistry. Herein, a transition-metal- and ligand-free, base-catalyzed regioselective C(sp³)-Si bond activation of silacyclobutanes (SCBs) and benzosilacyclobutenes (BSBs) has been developed. The protocol features a simple catalytic system that proceeds smoothly under air atmosphere without requiring inert gas protection. A variety of SCBs and BSBs are competent substrates, along with a range of nucleophiles as coupling partners. Furthermore, the strategy provides a straightforward platform for the late-stage functionalization of various bioactive molecules, enabling access to diverse quaternary silicon-containing scaffolds. Preliminary mechanistic investigations indicate that the C-Si bond cleavage is involved in the rate-determining step, and the hydrogen source originates from the nucleophile. In addition, the proposed mechanism is consistent with our experimental results and further supported by DFT calculations.