Selective Coupling of 1,2‐Bis‐Boronic Esters at the more Substituted Site through Visible‐Light Activation of Electron Donor–Acceptor Complexes

1,2-Bis-boronic esters are useful synthetic intermediates particularly as the two boronic can be selectively functionalized. Usually, less hindered primary ester reacts, but herein, we report a coupling reaction that enables reversal of this selectivity. This is achieved through formation boronate complex with an electron-rich aryllithium which, in presence electron-deficient aryl nitrile, leads to electron donor–acceptor complex. Following visible-light photoinduced transfer, radical generated which isomerizes more stable secondary before radical-radical arene radical-anion, giving β-aryl products. The reactions proceed under catalyst-free conditions. method also allows stereodivergent cyclic cis-1,2-bis-boronic provide trans-substituted products, complementing selectivity observed Suzuki–Miyaura reaction.