Catalyst-Free Synthesis of Trifluoromethylated Five- and Seven-Membered Nitrogen-Containing Heterocycles via Aza-Michael Addition and Lactamization of Trifluoroethylene Oxindoles

A novel protocol for the synthesis of trifluoromethylated pyrazolidiones and 1,5-benzodiazepinones was reported. In this strategy, hydrazines and 1,2-diaminobenzenes were used as binucleophiles to react with isatin-derived trifluoroethylene oxindole acrylates under catalyst-free conditions, and an aza-Michael addition/lactamization process occurred to give the corresponding products in good yields. Both cis and trans diastereoisomers of pyrazolidinones were obtained, and the possible mechanism and stereochemistry of this reaction was also discussed.