Design and synthesis of piperidine-containing sphingoid base analogues.

We report an approach that allows the efficient synthesis of the designed sphingoid base analogues in which the conformational restriction is introduced by incorporation of a cyclic moiety between the 2-amino group and the C-4 carbon atom of the sphingoid base. Our synthesis features a tandem enyne/diene-ene metathesis reaction that provides access to the designed framework. The diene moiety of the metathesis product is stereoselectively elaborated for the synthesis of the designed analogues. The preliminary biological evaluation indicates that the designed constrained analogues are much more effective than prototype natural sphingoid bases at inhibiting cancer cell growth.