Reductive cleavage and subsequent transformations of 5-oxa-6-azaspiro[2.4]heptane-1-carboxylates

Abstract

Treatment of methyl 4,6-diaryl-5-oxa-6-azaspiro[2.4]heptane-1-carboxylates with zinc in acetic acid leads to cleavage of the N–O bond in the isoxazolidine ring with formation of 1,3-amino alcohols whose subsequent cyclization under the reaction conditions yields bi- or tricyclic lactams or lactones with retention of the three-membered ring.