A phosphine (methyl 3-deoxy-3-diphenylphosphino-4,6-O-phenylmethenyl-α-D-altropyra- noside, 3-MBPA) derived from carbohydrate, which is steric demanding and richer on electron than triphenyl-phosphine, has been evaluated as supporting ligand in the palladium-catalyzed Heck reaction. It is found that K₂CO₃ is suitable as base for the catalyst system Pd(OAc)₂/3-MBPA in N,N-dimethyl acetylamine, and excellent yields have been achieved by the loading of palladium source down to 0.5 mol% for styrene coupling with aryl bromides containing electron-donating substituent and aryl chlorides containing electron-withdrawing substituent. The regioselectivities of the arylation of styrene catalyzed by the system indicate that the ion path co-exists in the coordination-insertion step, although the neutral path is favorite, meaning that the oxygen atoms of 3-MBPA coordinate to palladium probably. Besides, the regioselectivities raise through the coordination of Br^－ to palladium center to favour the neutral path by adding TBAB.

Key words: carbohydrate, phosphine, palladium catalyst, Heck reaction, regioselectivity