Pseudohalogen chemistry. Part II. Heterolytic addition of thiocyanogen chloride to some symmetrical α-arylalkenes

Abstract

Thiocyanogen chloride reacts with cis- and trans-stilbene and acenaphthylene in the presence of a radical inhibitor in acetic acid in the dark at 25° to yield α-chloro-β-thiocyanates and α-acetoxy-β-thiocyanates. The rate of addition to trans-stilbene in acetic acid, methylene chloride, chloroform, and benzene decreases with decreasing solvating power of the solvents. The reactions are trans-stereoselective. A heterolytic mechanism, involving a two-step, kinetically controlled addition and the formation of an open carbonium ion is suggested. The stereochemistry is discussed in terms of ion-pairs and steric control of reaction by the thiocyanato-group of the carbonium ion.