Diels-alder reactions with 2,2-bis (trifluoromethyl)-ethylene-1,1-dicarbonitrile as dienophile

Article abstract of DOI:10.1016/S0040-4039(00)76886-9

In the cycloadditions of the title compound BTF to methylated and phenylated butadienes, NMR spectra of adducts allow to draw the demarcation line between [4+2] and [2+2] cycloadditions. 1-Substituted butadienes accept BTF in the direction less hindered by the bulky CF₃groups. In rate comparison with TCNE, BTF shows electronic acceleration and steric deceleration.