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 Pd 2 (dba) 3 and ( p -ClPh) 3 P 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 PdCl 2 and (2',6'-dimethoxy-[1,1'-biphenyl]-2-yl)diphenylphosphine ( L1 ).