N-Substituted trifluoroacetimidoyl halides: Synthesis and properties
N-Substituted trifluoroacetimidoyl halides in ionic-type transformations readily undergo nucleophilic substitution and dehydrofluorination rather than 1,3-dehydrohalogenation to give nitrile ylides.
Sigmatropic isomerizations in azaallyl systems: XXII. 1,3-proton transfer in (N-alkyltrifluoroacetimidoyl)phosphonates
The reaction of N-alkyltrifluoroacetimidoyl chlorides with trialkyl phosphites leads to corresponding imidoylphosphonates CF 3C[P(O)(OAlk)2]=NCH2R. These compounds undergo irreversible 1,3-H shift catalyzed by nitrogenous bases to give phosphorylated imines CF3CH[P(O)(OAlk)2]N=CHR. The tendency for prototropism increases with increasing electronegativity of substituents R: CF3 > CH2OMe > H > Me. N-Cyclopentyl analogs of the obtained compounds show no tendency for prototropism. Imidoylphosphonates exist mainly as Z isomers [Z/E (6-10) : 1].