Trifluoroacetaldehyde N-tosylhydrazone as a reagent for trifluoroethylation of terminal alkynes

Abstract

Application of trifluoroacetaldehyde N-tosylhydrazone as a new trifluoroethylating reagent for terminal alkynes is reported. This compound acts as an analog of 2,2,2-trifluorodiazoethane, devoid of such drawbacks as volatility, toxicity, storage instability, and explosion hazards. The CuI-mediated C–H insertion reaction of trifluoroacetaldehyde N-tosylhydrazone into terminal alkynes demonstrated its broad applicability in the synthesis of trifluoroethyl-substituted acetylenes under mild basic conditions. This method provides high yields and compatibility with a wide range of functional groups.