Synthetic Applications of Cyclopropenethiones and Cyclopropenyl Cations

Abstract

The synthetic applications of tris(t-butylthio)cyclopropenyl cation (1) and 2,3-bis(t-butylthio)cyclopropenethione (7) which have highly strained three-membered rings have been examined. A one-pot reaction of 1 with lithium 2-methylpiperidinide at -78°C gave N-heterocyclic compound 6. The reaction of 1 with substituted ethynyl anions gave ethynylallene derivatives 3a-c in good yields. Furthermore, the reaction of 7 with thionylchloride at 0°C, followed by treatment with ethynyl anions, afforded the diethynylallene derivative 9. The structures of 3c and 6, were determined by X-ray analyses. Features of the above synthetic reactions and properties of products are presented.