C2-symmetric cyclic selenium-catalyzed enantioselective bromoaminocyclization.

A catalytic asymmetric bromocyclization of trisubstituted olefinic amides that uses a C(2)-symmetric mannitol-derived cyclic selenium catalyst and a stoichiometric amount of N-bromophthalimide is reported. The resulting enantioenriched pyrrolidine products, which contain two stereogenic centers, can undergo rearrangement to yield 2,3-disubstituted piperidines with excellent diastereoselectivity and enantiospecificity.