Synthesis of 4-Trifluoromethylated 2-Alkyl- and 2,3-Dialkyl-Substituted Azetidines

A diastereoselective approach to the synthesis of 4-trifluoromethylated 2-alkyl- and 2,3-dialkylazetidines, including BOC-protected 4-trifluoromethylazetidin-2-ylcarboxylic acid, was developed via Wittig reaction of 4-trifluomethylated β-lactam followed by alkylation and hydrogenation.