An Olefinic 1,2‐Boryl‐Migration Enabled by Radical Addition: Construction ofgem‐Bis(boryl)alkanes

• DOI: 10.1002/anie.201903721
• Publication Date: 2019-05-06T20:46:21Z
• Authors: Binlin Zhao; Zexian Li; Yixiao Wu; Yandong Wang; Jiasheng Qian; Yu Yuan; Zhuangzhi Shi

A series of in situ formed alkenyl diboronate complexes from Grignard reagents (commercially available or prepared bromides and Mg) with B2 Pin2 (bis(pinacolato)diboron) react diverse alkyl halides by a Ru photocatalyst to give various gem-bis(boryl)alkanes. Alkyl radicals add efficiently the complexes, adduct radical anions undergo radical-polar crossover, specifically, 1,2-boryl-anion shift boron α-carbon sp2 center. This transformation shows good functional-group compatibility can serve as powerful synthetic tool for late-stage functionalization complex compounds. Measurements quantum yield reveal that radical-chain mechanism is operative which diboronates acts reductive quencher excited state photocatalyst.