The Knoevenagel-Michael-Mannich-cyclization cascade of aldehydes, cyano-containing C-H acids, ethyl 4,4,4trifluoro-3-oxobutanoate and ammonium acetate provided convenient stereoselective formation of ethyl 5,5dicyano-4,6-diaryl-2-hydroxy-2-(trifluoromethyl)pi-peridine-3-carboxylates with four stereogenic centers and dialkyl 4,6-diaryl-5-cyano-2-hydroxy-2-(trifluoromethyl)piperidine-3,5-dicarboxylates with five stereogenic centers. The stereoselective formation of individual diastereomers was shown. The configuration of diastereomers was confirmed by NMR spectra and X-ray diffraction analysis. Ammonium acetate played dual role, acting as a base and as a nitrogen source.

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