preparation and reaction of 2-chloroperflurorocycloalkeny1(C6,C3) metal (Cu,Zn) reagents

Abstract

I. Preparation and reactions of 2-chloroperfulorocycloalkenyl $(C_6, C_3)$ Metal (Cu, Zn) reagents : 1-chloro-2-iodooctafluoro-cyclohexene reacted with activated zinc powder in DMF solvent at room temperature to give 2-chlorooctafluorocyclohex-1-enyl zine iodide. Treatment of this organozinc reagent with CuBr at room temperature for 1 hr provided a simple route to the 2-chlorooctafluorocyclohex-1-enyl copper reagent in excellent yield. This copper reagent exhibited excellent thermal stability at room temperature in the absence of oxygen and/or moisture. Alkylation reaction of this organocopper reagent were performed, and the reaction of this copper reagent with acyl haides gave acylated polyflourocyclohexenes, which have not been reported in the literature. 2-Chloro-3,3-difluorocycloprop-1-enylzinc iodide was also prepared from 1-chloro-3,3-difluoro-2-iodocyclopropene with acid washed zinc powder in good yield in DMF/HMPA cosolvent. This zinc reagent exhibited excellent stability at room temperature in the absence of oxygen and/or moisture. The reaction of this zinc reagent with a various of acyl and alkyl halides was found to be catalyzed by CuBr and represents a convenient root to the synthesis of vinylic substituted 3,3-difluorocyclopropene derivatives. In this reaction, HMPA was a useful cosolvent. A mechanistic interpretation may be explained by oxidative addition and reductive elimination. Oxidative addition of an alkyl halide to the copper(I) reagent yield a plannar copper(III) intermediate. Reductive elimination of two organic ligands from the copper(III) intermediate lead to a coupled product and Cu(I) species