6) Aliphatic difluoromethyl diazirines. Next, we wondered if the strategy for aliphatic trifluoromethyl diazirines could also be extended to the difluoromethylated analogues. Importantly, aliphatic CHF 2 -diazirines were unknown in the literature before. As a representative example, we first synthesized the azetidine derivative. Commercially available amino acid was converted first into the difluoromethyl ketone 28c following literature protocol (Scheme 3). Subsequent reaction of the latter with hydroxylamine gave oxime 28d in 69% yield. O-mesylation (28e), reaction with liquid ammonia, and oxidation provided N-Boc diazirine 28f in 50% yield. Final acidic deprotection of N-Boc gave the needed CHF 2 -azetidine 28g‧HCl in 22% yield. Synthesis of the difluoromethyl piperidine 29g‧HCl was also analogously performed following this strategy from carboxylic acid 29a in 19% overall yield and 20 g scale (Scheme 3).