Base-mediated allylation of N-2,2,2-trifluoroethylisatin ketimines and its application in aza-Prins reactions

The aza-Prins reaction of allylic imines triggered by N-2,2,2-trifluoroethylisatin ketimine is accomplished for the synthesis of spirooxindole derivatives involving trifluoromethyl group in the presence of TMSX. This cyclization reaction is operationally simple and proceeds under mild conditions using non-toxic reagents. Notably, while the previous our work could not be compatible with TMSX (X = Cl, I, etc) in one-pot process, this work describes successful aza-Prins reaction with TMSX (X = Cl, I, etc) via step-by-step process.