Studies on the rearrangement of (trichloromethyl)carbinols to α-chloroacetic acids

Abstract

Phenyl(trichloromethyl)carbinol undergoes an unimolecular, predominantly intramolecular conversion into potassium α-chlorophenylacetate on stirring with 10 % aqueous potassium hydroxide at 0 °C for several days. Besides providing an interesting example of a 1–2 chlorine shift, the reaction is of potential importance for the synthesis of α-chloro acids. The study of a variety of (trichloromethyl)carbinols shows the reaction is general for secondary (trichloromethyl)carbinols as well as trichloroethanol. The mechanism of the reaction involves the preliminary formation of an epoxide. Several mechanisms are considered for the conversion of the epoxide to the α-chloroacetate anion, but none accounts for all of the experimental facts. Tertiary carbinols break down at the epoxide stage into a ketone and carbon monoxide.