Cross-coupling reactions with boronic acids in water catalysed by oxime-derived palladacycles

Abstract

Palladacycles derived from phenone-oximes 1 are efficient precatalysts for the Suzuki–Miyaura coupling of arylboronic acids with aromatic and heteroaromatic bromides and chlorides under water reflux under aerobic conditions. Alternatively, the coupling can also be carried out at room temperature in methanol–water. Aryl bromides gave biaryls with TON up to 10 5 and TOF up to 7×10 4 h −1. Activated and deactivated aryl chlorides need the presence of TBAB for the couplings, showing slightly lower efficiency (TON up to 9000 and TOF up to 3850 h −1). C(sp 2)C(sp 3) bonds can also be formed by cross-coupling reactions of trimethylboroxine and butylboronic acid with aromatic bromides and chlorides under water reflux and of benzylic and allylic chlorides or acetates with arylboronic acids in acetone–water at room temperature.