Extended Data Fig. 2: Further studies in O-to-N swap with complex amines.

L-Phenylalanine methyl ester, mexiletine and oseltamivir underwent reaction with 8 to give the corresponding azetidine products. Ac, acetyl.

L-Phenylalanine methyl ester, mexiletine and oseltamivir underwent reaction with 8 to give the corresponding azetidine products. Ac, acetyl.