The kinetics and mechanisms of additions to olefinic substances. Part XI. Stereochemistry of addition of chlorine acetate and of chlorine to some unsaturated compounds

Abstract

The proportions of diastereoisomeric acetoxy-chlorides formed by addition of chlorine acetate to methyl cinnamate and to some of its derivatives, to phenanthrene, to acenaphthylene, and to cyclohexene have been estimated in acetic acid as solvent under a number of conditions. In a number of cases the ratios differ markedly from those of the same products formed by addition initiated by electrophilic chlorine in the same solvents. Different carbonium ion intermediates must be involved in the reactions initiated by the two reagents; the mechanisms of these reactions are discussed. It is concluded that the reactions initiated by chlorine acetate involve sequences in which the products come largely from chloronium ions, whereas those initiated by chlorine involve sequences in which the products often come from zwitterionic intermediates.