Fluoro-containing allenes react easily with isonitriles. Tetrakis(trifluoromethyl)allene gives the addition product of two molecules of the isonitrile to one double bond of the allene, while unsymmetrical 1,1-dicarbethoxy-3,3-bis(trifluoromethyl)allene gives the 1,4-cycloaddition product of one molecule of the isonitrile with involvement of the carbethoxyl group of the allene.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1904–1905, August, 1974.