We next the scope of groups on the nucleophilic nitrogen atom by replacing the tosyl group (Table ). This attempt revealed that only tosylamide enabled the formation of azetidine rings under the optimal reaction conditions. Sulfinamide 4b, the synthetic intermediate of chiral (R)-4a, was selectively cyclized to five-membered sulfinamide 5b (X-ray structure in Supporting Information) by the preferential nucleophilic attack of a sulfur atom with stereochemical inversion. Nosylamide 4c was not a suitable substrate for this reaction. The use of common protective groups such as tert-butoxycarbonyl (Boc) or carboxybenzyl (Cbz) led to the formation of six-membered products 5d or 5e respectively.