Investigation of the stereochemistry of the radical telomerization of propylene by polyhalomethanes by the method of conformational PMR analysis

Abstract

1. The stereochemical radical telomerization of propylene with CCl4 and CBrCl3 was investigated by the method of conformational PMR analysis at 60°. The relative configurations of diastereomeric racemic forms of the telomer CCl3CH2CH(CH3)CH2CHBrCH3 were established according to conformational data, considering the previous independent assignments for CCl3CH2CH(CH3)CH2CHCICH3 and structurally close chiral polychloroalkanes. 2. The reactions of chain transfer to CCl4 and CBrCl3 forα, γ-disubstituted aliphatic radicals have the same stereodirection. The approach of the telogen to the radical from the side opposite to the position of the substituent in the next-to-last monomer unit proved to be the preferential direction of attack. 3. Differences in the parameters of the PMR spectra of diastereomeric forms of nonsymmetrical polyhalosubstituted aliphatic hydrocarbons with two chiral centers from the similar dissymmetrical compounds retaining certain elements of symmetry, important for the assignment of the configurations, were detected.