Stereochemistry and kinetics of nucleophilic substitution of activated 1,1-diaryl-2-halogenoethylenes. Part II

Abstract

Geometrical isomers of 2-chloro-1-p-nitrophenyl-1-phenylethylene undergo chloride exchange with labelled lithium [³⁶Cl]chloride in dimethylformamide, retaining their configuration. Reaction rates of these compounds, as well as of 2-chloro-1,1-di-(p-nitrophenyl)ethylene and of the corresponding bromo-ethylenes were measured as a function of temperature, within the range 50–140°. Lithium chloride proved a much weaker nucleophile than sodium toluene-p-thiolate, by a factor of 10⁹–10¹⁰(at 24°) in the case of the 2-halogeno-1-p-nitrophenyl-1-phenylethylenes.