Aldol-crotonic condensation of allobetulone and betulonic aldehyde with N-substituted pyrrole-2and pyrazole-4-carbaldehydes afforded a series of new α,β-unsaturated ketones of lupane series. Their reduction provided 2-ylidene derivatives of allobetulin and betulin, potential chiral components of liquid crystal materials. Structures of 1were established by X-ray diffraction (XRD) study .

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Methylenation of (3R,6R) 2 (4 X benzylidene) 6 isopropyl 3 methylcyclohexanones (X = F, Cl, Ph) with dimethylsulfoxonium methylide occurs stereoselectively to give 1(S) (4 X phenyl) 5(R) isopropyl 8(R) methyl 3(R) spiro[2.5]octanones, whose stereochem istry was established by 1 H NMR spectroscopy. The configuration of the chiral centers in the cyclohexanone fragment and its preferred conformation (methyl is axial and isopropyl is equatorial) in the products do not change with respect to the starting enones. The mutual trans arrangement of the carbonyl and aryl groups at the newly formed three membered ring was established; the aryl group also occupies the trans position with respect to the axial methyl group of the cyclohexanone fragment. Using methylenation of the compound with X = Ph as an example, a mixture of by products resulting from oxidative hydroxylation at the α position relative to the carbonyl group was isolated. The resulting chiral spiro[2.5]octanones induce a helical supramolecular ordering in the nematic mesophase of 4 pentyl 4´ cyanobiphenyl and exhibit a twisting power only somewhat (by 20-30%) lower than the starting enones.