Regioselective one-step alkoxy-aryloxycarbonylation of alkenes

The direct alkoxy-aryloxycarbonylation reaction of olefins has been realized for the first time. Under palladium(II) catalysis and with p-benzoquinone as oxidant, various olefins (aromatic, aliphatic and 1,2-disubstituted), alcohols (primary, secondary and tertiary) and phenols (with different para, meta and ortho substituents) have been converted in one-step into mixed alkyl aryl succinates in moderate to excellent yields (up to 90%). The reaction is completely regioselective, as the aryl ester moiety was consistently observed on the more substituted carbon of the starting alkene double bond. Based on experimental results and detailed DFT calculations, a plausible catalytic cycle has been proposed, accounting for the observed regioselectivity. Interestingly, from our computation studies, benzoquinone was found to be crucial not only to regenerate the catalytic active species, but also for promoting the final elimination step, leading to the desired succinate. Finally, some reactions were performed to prove the different chemical behavior of the two installed ester groups.