Preparation of acyl(carboxylato)bis(tertiary phosphine)palladium(II) complexes by C-O bond cleavage of carboxylic anhydrides on interaction with palladium(0) complexes. Catalytic hydrogenation of carboxylic anhydrides to aldehydes by palladium complexes

Acyclic anhydrides oxidatively added to [Pd(styrene)(PMeR₂)₂] (R = Me, 2a; Ph, 2b) under mild conditions with C-O bond cleavage to give the corresponding trans-acyl(carboxylato)palladium complexes 3a-3h. Cyclic acid arthydrides also added to 2a to yield trans-acyl(carboxylato)palladium complexes 4a-4c, while reaction of 2a with phthalic anhydride afforded the palladalactone 4d generated via oxidative addition followed by decarbonylation. The acetyl(acetato)palladium complex 3a reacted with dihydrogen or formic acid to give acetaldehyde and acetic acid. Catalytic hydrogenation of acyclic anhydrides by a palladium complex was achieved to form the corresponding aldehydes and carboxylic acids.