ASYMMETRIC ALKENYLATION OF CHIRAL AND PROCHIRAL ALDEHYDES CATALYZED BY CHIRAL OR ACHIRAL AMINO-ALCOHOLS - CATALYTIC DIASTEREOSELECTIVE SYNTHESIS OF PROTECTED ERYTHRO-SPHINGOSINE AND ENANTIOSELECTIVE SYNTHESIS OF CHIRAL DIALLYL ALCOHOLS

Protected D-erythro-(2S,3R)-sphingosine was preferentially obtained by diastereoselective pentadec-1-enylation of tert-butyl (S)-4-formyl-2,2-dimethyloxazolidine-3-carboxylate with pentadec-1-enyl(ethyl)zinc using either (R)-diphenyl(1-methylpyrrolidin-2-yl)methanol (DPMPM) as a chiral catalyst or 2-(dibutylamino)ethanol as an achiral catalyst. Enantioselective alkenylation of alpha,beta-unsaturated aldehydes using (S)-DPMPM as a chiral catalyst affords chiral diallyl alcohols with good enantiomeric excesses.