Palladium(0)-Catalyzed Alkoxycarbonylation of Allyl Phosphates and Acetates

Article abstract of DOI:10.1021/jo00058a040

Palladium-catalyzed alkoxycarbonylation of allyl phosphates under CO (1 atm) at 50 deg C proceeds highly efficiently to give the corresponding β,γ-unsaturated esters.The carbonylation of geranyl phosphate ((E)-11) under CO (1 atm) at 50 deg C gave ethyl ester of homogeranic acid ((E)-12) stereoselectively.The carbonylation takes place at least substituted allylic positions with inversion of configuration.Typically, the methoxycarbonylation of cis-5-(methoxycarbonyl)-2-cyclohexen-1-yl phosphate (cis-16) gave trans-dimethyl-2-cyclohexene-1,5-dicarboxylate (trans-17) selectively.Alkoxycarbonylation of allyl acetates is performed for the first time in the presence of a catalytic amount of bromide ion.The reaction can be rationalized by assuming the mechanism which involves oxidative addition of palladium(0) species to allyl acetates to give ?-allylpalladium acetate, fast ligand exchange of the acetate with bromide, insertion of carbon monoxide to give acylpalladium species, and alkoxylation.