Versatile Synthesis of α‐Oxygen Organoboron Compounds via Photo‐Induced Siloxycarbene^†.

Comprehensive Summary: A novel method for synthesizing α‐oxygen organoboron compounds has been developed through acylsilane‐based carbene insertion reactions into C—B bonds. As coupling partners, readily available organoboron compounds (alkenyl, allyl, and allenyl B(pin)) were employed. Based on the substrates, pure insertion into C—B bonds or insertion followed by a siloxy group rearrangement process (from carbon to boron) would occur, delivering the α‐oxygen organoboron compounds with great diversities. Control experiments demonstrated that the electronic effect of the substituents mainly controlled the rearrangement process. Besides, no matter which isomer of substrate (Z or E) was used, the reaction with β‐aryl‐substituted alkenyl B(pin) affords both isomers of products (Z and E, separable through column chromatography). Trapping experiments indicated the triplet energy transfer process was involved. [ABSTRACT FROM AUTHOR]