Scandium(III) Perfluorooctanesulfonate [Sc(OPf)3] : A Novel Catalyst for the Hetero Diels–Alder Reaction of Aldehydes with Non-Activated Dienes

Scandium(III) perfluorooctanesulfonate [scandium(III) perflate, Sc(OPf)3] was prepared from either scandium(III) chloride or oxide and perfluorooctanesulfonic acid. The perflate thus obtained acts as a novel Lewis acid catalyst for the intermolecular hetero Diels–Alder reaction of aldehydes with non-activated dienes under mild conditions. The characteristic features of the catalyst include (i) low hygroscopicity, (ii) ease of handling, and (iii) robustness for the recycling use.