Chlorovinylidenecarbene: generation from 3,3-dichloropropyne by interaction with potassium hydroxide under phase-transfer catalysis conditions and reactions with alkenes

Chlorination of propargyl aldehyde with PCl₅ in CH₂Cl₂ at –20 °C in the presence of catalytic amounts of pyridine afforded dichloromethylacetylene. Reaction of the latter with powdered KOH under phase-transfer catalysis conditions gave chlorovinylidenecarbene due to -elimination of HCl. In the presence of alkenes the carbene undergoes addition at the double bond giving chlorovinylidenecyclopropanes in 20–45 % yields.For the previous communication, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1242–1244, July, 1993.