Asymmetric synthesis of N,O,O,O-tetra-acetyl d-lyxo-phytosphingosine, jaspine B (pachastrissamine), 2-epi-jaspine B, and deoxoprosophyllinevialithium amide conjugate addition

Abstract

The highly diastereoselective anti-aminohydroxylation of (E)-γ-tri-iso-propylsilyloxy-α,β-unsaturated esters, viaconjugate addition of lithium (S)-N-benzyl-N-(α-methylbenzyl)amide and subsequent in situ enolate oxidation with (+)-(camphorsulfonyl)oxaziridine, has been used as the key step in the asymmetric synthesis of N,O,O,O-tetra-acetyl D-lyxo-phytosphingosine (20% yield over 7 steps), the anhydrophytosphingosine jaspine B (10% yield over 9 steps), 2-epi-jaspine B (14% yield over 9 steps), and the Prosopisalkaloid deoxoprosophylline (26% yield over 7 steps).