Photocatalytic [3 + 2]-annulation via sodium tetraarylborate: a fundamental approach for synthesizing 1,4,2-diazaborole analogs

Nitriles stabilize neutral diarylboryl radicals, generating the RCN-BAr 2 complex, an efficient boron-nitrogen synthon that reacts with imines and olefins for photocatalytic synthesis of boron–nitrogen heterocycles, such as 1,4,2-diazaboroles.