Stereospecific Amination by Dynamic Kinetic Resolution Utilizing 2-Oxoimidazolidine-4-carboxylate as a Novel Chiral Auxiliary

Article abstract of DOI:10.1021/jo00126a029

A novel type of stereospecific amination by dynamic kinetic resolution using (4S)-2-oxoimidazolidine-4-carboxylate (1) as a chiral auxiliary was developed. A reaction of a diastereomeric mixture of (4S)-3-<(2RS)-2-bromoacyl>-2-oxoimidazolidine-4-carboxylates 4 with an amine in the presence of a base in HMPA predominantly afforded (4S)-3-<(2R)-2-(alkylamino)acyl>-2-oxoimidazolidine-4-carboxylates (S,R)-7 in good yields.The reaction proceeded by stereospecific S_N2 type amination incorporated with rapid interconversion between the substrates (S,S)-4 and (S,R)-4.Mechanistic study suggested that the unique stereoselectivity was induced through the interaction between an amine and the ester group of (S,S)-4 in the transition state.The chiral auxiliary was easily removed with alkoxide anion to afford the α-amino acid synthon in good yields.