An efficient synthesis of optically active 3-amino-3-alkyl-2-oxetanones

An efficient two-step synthesis of p-toluenesulfonic acid salts of optically active 3-amino-3-alkyl-2-oxetanones is reported that involves cyclization of N-Boc-α-alkylserines under Mitsunobu reaction conditions followed by deprotection of the amino group with trifluoroacetic acid in the presence of anhydrous p-toluenesulfonic acid.