Synthesis and properties of N-(alkenylidene)trifluoromethanesulfonamides

Resumo

N-Alkenylidenetrifluoromethanesulfonamides TfN=CH–CR=C(Me)R′ (R, R′ = H, Me) have been synthesized by reaction of N-sulfinyltrifluoromethanesulfonamide TfNSO with (E)-but-2-enal, (E)-2-methylbut- 2-enal, and 3-methylbut-2-enal. Despite greater stability of N-alkenylidenetrifluoromethanesulfonamides relative to their propargyl isomers TfNHCH₂C≡CR, no rearrangement of the latter into the former occurs due to the presence of an acidic NH proton, which hampers formation of carbon-centered anion.