Pseudohalogen chemistry. Part I. Heterolytic addition of thiocyanogen chloride to some symmetrical alkenes and cycloalkenes
Thiocyanogen chloride reacts rapidly with ethylene, cis- and trans-but-2-ene, cyclohexene, and trans-Δ2-octalin in the presence of a radical inhibitor in acetic acid in the dark to yield α-chloro-β-thiocyanates and α-acetoxy-β-thiocyanates. The reaction is trans stereospecific. A heterolytic mechanism, involving a two-step, kinetically controlled addition and the formation of a cyano-sulphonium ion intermediate [e.g. (VIII)] is suggested.