Isolation of Bicyclopropenylidenes: Derivatives of the Smallest Member of the Fulvalene Family


  • Financial support from the NSF (CHE 0808825) is gratefully acknowledged. We also thank the JSPS for Fellowships (R.K. and Y.I.) and Dr. J. C. Daran for his help with the crystallographic part of this manuscript.


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Small and stable: A triafulvalene derivative is indefinitely stable at room temperature both in solution and in the solid state under inert atmosphere. The triafulvalene is synthesized by the magnesium-catalyzed coupling of two bis(chlorocyclopropenyl) derivatives. The two unsaturated three-membered rings are linked together by a carbon–carbon double bond (1.303 Å, see structure), which is so reactive that spontaneous addition of water occurs at room temperature.