Lewis Acid-Catalyzed [3+2] cycloaddition of Donor-Acceptor cyclopropanes and enamines: enantioselective synthesis of Nitrogen-Functionalized cyclopentane derivatives

Abstract

A straightforward and efficient method for the synthesis of nitrogen-functionalized cyclopentane derivatives via [3+2] cycloaddition of enamines with donor-acceptor cyclopropanes in the presence of catalytic amounts of various Lewis acids at room temperature has been developed; furthermore, the corresponding b-amino acid was synthesized by monodecarboxylation and hydrogenolysis. An enantioenriched synthesis of nitrogen-functionalized cyclopentane derivatives through dynamic kinetic asymmetric transformation of racemic donor-acceptor cyclopropanes has also been achieved employingacopper complex [Cu(OTf)2 -L1] as the catalyst affording an enantiomeric ratio up to 8:1.