Pd-catalyzed alkoxycarbonylation of alkenes promoted by H2O free of auxiliary acid additive

The Pd-catalyzed alkoxycarbonylation of alkenes using water as a promoter has been scarcely reported before. Herein, water instead of Brønsted/Lewis acid was found to effectively improve the catalytic performance of Pd(MeCN) 2 Cl 2 -Xantphos system for alkoxycarbonylation of alkenes. Under the optimal conditions, the best yield of 97% was obtained for the target products (methyl 3-phenylpropanoate and methyl 2-phenylpropanoate) with L/B of 4.3 and TON of 192. With the involvement of water, Pd(MeCN) 2 Cl 2 -Xantphos system also exhibited the moderate to good generality to alkoxycarbonylation of different kinds of alkenes with alcohols. The in situ high pressure FT-IR analysis verified that water played an important role in promoting formation and stability of Pd H active species which was responsible for the efficient alkoxycarbonylation of alkenes. In addition, the ligand effect of Xantphos on this reaction was discussed.