Selective C–O bond cleavage of allylic esters using [MoH4(Ph2PCH2CH2PPh2)2] under light irradiation to give hydridocarboxylatomolybdenum(II) complexes
Abstract
The complex [MoH4(dppe)2](1)(dppe = Ph2PCH2CH2PPh2) reacted with allyl carboxylates RCO2CH2CHCH2(R = H, Me, Et, Prn, But, CH2CMe, or Ph) in benzene upon irradiation with a high-pressure mercury lamp to give [MoH(O2CR)(dppe)2](2), together with propene and H2. Reaction pathways comprising the oxidative addition of the allyl carboxylates involving allyl–oxygen bond cleavage are proposed on the basis of the results obtained with substituted allylic esters. The complexes (2) were characterized spectroscopically as having pentagonal-bipyramidal structures in solution. The similar reaction of complex (1) with allyl formate led to selective cleavage of the formic C–H bond to give ultimately the known cis-[Mo(CO)2(dppe)2]via(2; R = H).