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

Abstract

cis- and trans-Isomers of 2-chloro-1-p-nitrophenyl-1-phenylethylene were prepared and identified by their dipole moments and spectroscopic properties. Their reactions with sodium toluene-p-thiolate in dimethylformamide, as well as the reactions of the corresponding bromo-derivatives, proceed as direct substitutions with retention of configuration. A kinetic study has shown that (k_trans/k_cis)= 2·9 for chloroethylenes and 1·4 for bromoethylenes at 24°. 2-Chloro-1,1-di-p-chlorophenylethylene was also kinetically tested.