Short asymmetric syntheses of sphinganine [(2S,3R)-2-aminooctadecane-1,3-diol] and its C(2)-epimer

Abstract

A short asymmetric synthesis of sphinganine [(2S,3R)-2-aminooctadecane-1,3-diol] and its C(2)-epimer is reported. The synthesis of sphinganine employs diastereoselective aminohydroxylation of tert-butyl 2-octadecenoate [conjugate addition of lithium (S)-N-benzyl-N-(α-methylbenzyl)amide, then in situ enolate oxidation with (+)-camphorsulfonyloxaziridine (CSO)] and a stereospecific rearrangement of the resultant anti-α-hydroxy-β-amino ester into the corresponding anti-α-amino-β-hydroxy ester. Final hydrogenolysis and ester reduction completes the synthesis of the sphingoid base target. The synthesis of the C(2)-epimer follows a similar route, incorporating a diastereoselective reduction protocol to transform the anti-α-hydroxy-β-amino ester into its syn-α-hydroxy-β-amino ester counterpart.