Pd-Catalyzed Regioselective Hydrocarboxylation of Alkyl Terminal Olefins with Oxalic Acid.

A Pd-catalyzed regioselective hydrocarboxylation of alkyl terminal olefins with oxalic acid is described. A wide variety of linear carboxylic acids can be readily obtained in good yields and high l/b (linear/branched) ratios with Pd2(dba)3 and (p-ClPh)3P under mild conditions. The reaction process is operationally simple and requires no handling of toxic CO. In addition, branched carboxylic acids can also be formed in good regioselectivities with PdCl2 and (2',6'-dimethoxy-[1,1'-biphenyl]-2-yl)diphenylphosphine (L1).

Pd-Catalyzed Regiodivergent Hydrocarboxylation of Olefins with Oxalic Acid: A Remarkable Effect of the Counteranion on Regioselectivity.

A regioselective Pd-catalyzed hydrocarboxylation of vinyl arenes with oxalic acid is described. A wide variety of either linear or branched carboxylic acids can be readily obtained with high regioselectivities under mild reaction conditions. The reaction process is operationally simple and requires no handling of toxic CO. Besides the ligand, the counteranion of the Pd catalyst system plays an important role in the regioselectivity.