Chlorovinylidenecarbene: Generation from 3,3-Dichloropropyne by Base Solvolysis (under Phase-transfer Catalysis Conditions) and Reaction with Alkenes

The chlorovinylidenecarbene 6 has been generated from 3,3-dichloropropyne 1a via γ-elimination of hydrogen chloride on treatment with powdered KOH under phase-transfer catalysis conditions and has been trapped by alkenes, to form chlorovinylidenecyclopropanes 7 in 20–45% yields.