Under the optimal conditions, we examined the substrate generality of azetidine formation by introducing a substituent on the aromatic ring of substrates 4a (Table ). The formation of 5f -5h indicates that the electronic preference is similar to that for oxetanes 2v -2z. In contrast to unsuccessful 2v, azetidine 5f bearing p-methoxy phenyl could also be synthesized using this method. Encouraged by these results, we performed reactions yielding azetidines bearing sterically hindered mesityl (5i), 2-naphthyl (5j), and biphenyl (5k). Substrates derived from aliphatic aldimine were also applicable. For example, three azetidines 5l -5n could be synthesized, regardless of steric hindrance. Dichloromethane was a better solvent than toluene for addressing the solubility issue (5n). Compared with the case of oxetane 3ad (62%), azetidine 5o was formed in only 36% yield along with tetraline 5o′ (45%; Supporting Information). In contrast, the azetidine was selectively formed, regardless of the possible deprotective cyclization (5p). We synthesized two chiral bicyclic compounds bearing rotatable linkers 5q and 5r in acceptable yields. Both compounds were synthesized on a larger scale in similar yields. Furthermore, 2,2,4,4-tetrasubstituted azetidines were synthesized by this method. Again, we confirmed the requirement of the tosyl group by using the substrate bearing an indane framework; the yield of 5s bearing a tosyl group was higher than that of 5t bearing a nosyl group. The substrate bearing a Cbz group afforded six-membered 5s′ (see supporting information). The yields were not satisfactory for every product 5u, 5v, 5w, and 5x; however, it should be noted that the practical synthesis of these azetidines has not yet been reported. Unfortunately, this cycloisomerization afforded 5y or 5z in insufficient yields. Less substituted azetidines 5aa and 5ab were also synthesized using this method. Homoallylamine derivative 5ac could not be synthesized by this method. Overall, this cycloisomerization was found to be suitable for the synthesis of polysubstituted azetidines.