Quantum mechanics

Catalysis

Electron donor

Aryl radical

Acceptor

Boronic acid

Boron

Photochemistry

Metallurgy

Materials science

Coupling (piping)

Suzuki reaction

Electron acceptor

Alkyl

Electron transfer

Visible spectrum

Combinatorial chemistry

Physics

Organic chemistry

Condensed matter physics

Nitrile

Photoinduced electron transfer

Chemistry

Aryl

Selectivity

Electron

Optoelectronics

Angewandte Chemie International Edition

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

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