Stereoselective aldol reactions using pseudo C2 symmetric 1-benzyl-4-(trifluoromethyl)piperidine-2,6-dione.

Crossed aldol reactions of the CF3-containing pseudo C2 symmetric cyclic imide 3 were carried out by way of the corresponding boron bisenolate to stereoselectively furnish the desired products 4 and this procedure allowed the preferential construction of the diastereomers of the compounds previously obtained from the acyclic counterpart 1.