Palladium-catalyzed cyclization/allylation of in situ-generated α-hydroxy-[3]-cumulene samarium alkoxides: synthesis of allylated furans

Samarium alkoxides of α-hydroxy-[3]-cumulenes, generated in situ by SmI2-promoted reduction of appropriate epoxypropargyl esters, are found to participate in novel Pd-catalyzed cyclization/allylation sequences in the presence of allylic bromides. This results in the efficient regioselective formation of polysubstituted furans incorporating the allyl unit.