Water-promoted palladium-catalysed Heck cross-coupling reactions of aryl halides with alkenes in TBAB

摘要

Water was found to promote the ligand-free Pd(OAc)_2-catalysed Heck cross-coupling reaction. In the presence of 3 mol% Pd(OAc)_2, 2 equiv. of Cs_2CO_3 and 15 mg of water, the coupling of a wide variety of aryl halides with alkenes proceeded smoothly in TBAB (n-Bu 4NBr) in moderate to excellent yield. The Pd(OAc)_2/TBAB system could be recovered and reused at least three times without loss of catalytic activity.