The cyclopolymerization of N-Allyl-N-methyl(2-substituted allyl)amines. The structure of the polymers and low molecular weight products

Abstract

Mass and ¹³C nuclear magnetic resonance spectroscopy are used to determine the structures of the poly(N-methylpyrrolidines), poly(N-methylpiperidines) and low molecular weight products obtained from N-allyl-N-methyl(2-substituted allyl)amines by cyanoisopropyl radical induced cyclizations. The structures are used to determine the preferred site of initial radical addition to the diallylamine and the subsequent direction of cyclization of the intermediate azaheptenyl radicals. Steric interactions induced by the β-substituents tend to favour attack at the unsubstituted allyl group whereas conjugated substituents favour attack at the substituted group with the consequent formation of conjugation-stabilized radicals. Kinetically controlled cyclization to the pyrrolidines occurs in all cases except that of the t-butyl derivative in which steric interactions induce cyclization to both piperidine and pyrrolidine products.