[2+2] Photocycloadditions with Chiral Uracil Derivatives: Access to All Four Stereoisomers of 2-Aminocyclobutanecarboxylic Acid

Abstract

Starting from a single, chiral, bicyclic derivative of uracil, all four stereoisomers of 2-aminocyclobutanecarboxylic acid have been prepared in enantiomerically pure form, using a synthetic sequence which begins with a key photochemical [2+2] cycloaddition reaction and includes a practical cis to trans β-amino acid isomerisation procedure.