Kinetics of nucleophilic substitution by chloride ion in 1,1-diaryl-2-halogenoethylenes

Abstract

The reactivity of cis- and trans-2-chloro(bromo)-1-p-methoxyphenyl-1-phenylethylenes with ³⁶Cl-labelled lithium chloride has been tested in dimethylformamide at 170–186°. The stereochemical course of substitution has been followed by infrared analysis, which has revealed a partial inversion of configuration. Chloride–chloride exchange, isomerisation, and bromide–chloride displacement rate constants have been measured. The suggested mechanism for the substitution accounts for the experimental facts by assuming an intermediate carbanion.