Lewis Acid Catalyzed [1,3]-Sigmatropic Rearrangement of Vinyl Aziridines

Abstract
This paper details the copper-catalyzed ring expansion of vinyl aziridines to 3-pyrrolines. Broad substrate scope (24 examples) using tosyl- and phthalimide-protected vinyl aziridine substrates is observed. Cu(hfacac)2 was determined to be superior to all other catalysts tested.