Uses
Ichloroketene is a dichloroacetylating agent; it undergoes cyclization with a variety of substrates.
Preparation
Dichloroketene is typically prepared in situ by dehalogenation of trichloroacetyl halides or dehydrohalogenation of dichloroacetyl halides. Elimination of dichloroacetyl chloride with Triethylamine affords the desired ketene, although material formed in this manner is of limited reactivity. Reduction of Trichloroacetyl Chloride with Zinc/Copper Couple activated with either Phosphorus Oxychloride or 1,1- Dimethoxyethane provides fully reactive dichloroketene. Recently, thermal activation of Zinc dust was used to generate dichloroketene.
storage
Given the propensity of dichloroketene to dimerize or polymerize, the reagent must be made and used immediately. Polymeric material is obtained on heating or concentration of solutions of dichloroketene, and anhydrous conditions must be maintained.
