Stereochemical studies. Part 31. Ring closure reaction of cis- and trans-2-(bromomethyl)cycloalkylamines

Abstract

Cyclization of the cis- and trans-2-(bromomethyl)cycloalkylamines (7)–(12) to the fused-ring azetidines (13)–(17) was investigated. The first-order rate constants for azetidine formation as a function of the ring size are in the order: cycloheptane > cyclopentane > cyclohexane for the cis-isomers; and cycloheptane > cyclohexane for the trans-isomers. Azetidine formation could not be induced from trans-2-(bromomethyl)cyclopentylamine (8). A plot of the E_a values for the reactions as a function of ΔS, shows an isokinetic correlation, with the exception of the point for trans-2-(bromomethyl)cyclohexylamine (10), where the main reaction is elimination.