Construction of Dibenzosilinanes through Energy Transfer Catalysis.

Silacyclic compounds occupy a pivotal position in synthetic chemistry, medicinal chemistry, and materials science. Herein, we report a method for the synthesis of dibenzosilacyclohexane derivatives via in situ activation of Si-H bonds mediated by a triplet energy transfer (EnT)-enabled biradical intermediate. Isotope labeling experiments reveal that the reaction proceeds via a cascade involving 1,5-hydrogen atom transfer, dearomatization, and arene ring reconstruction. Radical trapping experiments and spectroscopic investigations corroborate the EnT mechanism. Derivatives obtained from this protocol show promise as photocatalysts.