β2, 2-Amino Acid N-Carboxyanhydrides Relying on Sequential Enantioselective C(4)-Functionalization of Pyrrolidin-2,3-diones and Regioselective Baeyer–Villiger Oxidation

Abstract

A catalytic enantioselective entry to β2, 2-amino acids enabling their direct coupling with nucleophiles is described. The approach is based upon an effective bifunctional Brønsted base catalyzed construction of a quaternary carbon stereocenter at C4 position of pyrrolidin-2,3-diones. Subsequent regioselective Baeyer–Villiger oxidation of the resultant adducts gives β2, 2-amino acid N-carboxyanhydrides as the reactive species, which can further react with nucleophiles. Following this strategy both, β2, 2-amino acid derivatives with different functionalities at the newly created stereocenter, and spirocyclic structures can be efficiently prepared.