Abstract
A thermal rearrangement reaction of (R)-1-bromo-2-benzylaminobutane hydrobromide gave 3-bromo-1-benzylaminobutane hydrobromide. The process was confirmed by formation of a four-membered cyclic amine, the azetidine. After optical resolution of the racemic azetidine obtained, the compound was analyzed by its hydrobromide. The absolute configuration was unambiguously determined as S. The azetidine ring is bent to have a dihedral angle of 153° at the diagonal through non-N atoms.