Abstract Several new 1, 1-dicyanoethylenes, which are potent dienophiles, were prepared in two or more steps by the condensation of fluorocarbonyl compounds with malononitrile. These include (NC) 2 C C (Cl) R f (R f is CF 3, C 2 F 5, and C 3 F 7) obtained from perfluorocarboxylic acid esters, KCH (CN) 2 and PCl 5, and CF 3 (CF 2 Cl) C C (CN) 2 from CF 3 COCF 2 Cl and malononitrile. Reaction of cyclopentadiene with these new ...
