Palladium-catalyzed biaryl-coupling reaction of arylboronic acids in water using hydrophilic phosphine ligands

Hydrophilic phosphine ligands possessing a carbohydrate side-chain, such as N-(4-diphenylphosphinophenyl)methyl gluconamide (9), N-[4-(2'-dicyclohexylphosphinobiphenyl)phenylmethyl] gluconamide (10), and N-[4-(2'-di-t-butylphosphinobiphenyl)]phenylmethyl gluconamide (11), were newly synthesized to carry out palladium-catalyzed biaryl coupling of arylboronic acids in a single aqueous medium. The catalyst prepared in situ from Pd(OAc)(2) and 10 exhibited a higher efficiency than that of 9, 11, Ph2P(m-C6H4SO3Na) (TPPMS) or P(m-C6H4SO3Na)(3) (TPPTS) for representative aryl bromides, chlorides, or triflates. The catalyst prepared in situ from Pd(OAc)(2) (0.001 mol%) and 10 (0.002 mol%) achieved 96,000 TON in the reaction of p-tolylboronic acid with 4-bromoacetophenone in water. (C) 2002 Elsevier Science Ltd. All rights reserved.