Mechanistic considerations for the consecutive cyclization of 2,3-dibromopropylamine hydrobromide giving a strained molecule, 1-azabicyclo[1.1.0]butane

Abstract

The effective formation of 1-azabicyclo[1.1.0]butane (2) by treatment of 2,3-dibromopropylamine hydrobromide (1) with n-BuLi could be understood considering a rational reaction pathway via both transition states 10 and 19 based on the intramolecular Br⋯Li+ coordination. A similar cyclization pathway starting from N-benzyl-3-bromopropylamine hydrochloride (17) to afford N-benzylazetidine (18) could also be postulated on the basis of a transition state 20 involving the intramolecular Br⋯Li+ coordination. © 2004 Pharmaceutical Society of Japan.