Nucleophilic substitution by thiolate ions in some 1,1-diaryl-2-halogenoethylenes

Abstract

Six 1,1-diaryl-2-arylthioethylenes were obtained by displacement of chloride or bromide ion from diaryl-halogeno ethylenes by aryl thiolate ions in amidic solvents.

The reaction of compounds (p-R-C₆H₄)₂C:CHCl (R = H, Me, and OMe) with sodium toluene-p-thiolate in dimethylformamide was studied kinetically in the range 30–90°. The order of reactivity is H > Me > OMe, with a high value of the Hammett ρ constant. The reaction appears a case of direct nucleophilic substitution at a non-activated vinylic carbon atom.