Tandem synthesis of trichloromethylated [3.3.3]propellanes from trichloroacetamidines and a ninhydrin–malononitrile adduct

The trichloroacetamidine intermediates, generated by addition of benzylamine derivatives to trichloroacetonitrile, react with the Knoevenagel condensation product of ninhydrin and malononitrile to afford trichloromethylated [3.3.3]propellanes, in good yields. When benzylamine was used, a plane-symmetrical spiro-compound was obtained.