Cyclobutylboranes are important synthetic precursors for introducing strained cyclobutyl groups, yet their efficient synthesis remains a significant challenge. The recent development in photochemistry concerning bicyclo1.1.0butanes (BCBs, which are highly reactive radical acceptors) offers a direct route to access these motifs using boryl radicals. Herein, we report an effective and mild photomediated borylation of BCBs with high regioselectivity, enabling the synthesis of a series of cyclobutylborane compounds bearing diverse substituents. Comprehensive mechanistic studies provide strong evidence of a radical process involving hydrogen atom transfer (HAT).
Yi et al. (Fri,) studied this question.