Asymmetric synthesis of N,O,O,O-tetra-acetyl d-lyxo-phytosphingosine, jaspine B (pachastrissamine) and its C(2)-epimer

The highly diastereoselective conjugate addition of lithium (S)-N-benzyl-N-(α-methylbenzyl)amide to a γ-silyloxy-α,β-unsaturated ester and 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, jaspine B (pachastrissamine) and its C(2)-epimer.

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Methyl (2S,3S,αS)-2-hydroxy-3-[N-benzyl-N-(α-methylbenzyl)amino]-4-tri-iso-propylsilyloxy-butanoateC29H45NO4Si[α]D22=+37.0 (c 2.3 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (2S,3S,αS)

Methyl (2S,3S)-2-hydroxy-3-[N-(tert-butoxycarbonyl)amino]-4-tri-iso-propylsilyloxy-butanoateC19H39NO6Si[α]D21=+17.3 (c 0.4 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (2S,3S)

(4S,5S)-2,2-Dimethyl-N(3)-tert-butoxycarbonyl-4-tri-iso-propylsilyloxymethyl-5-methoxycarbonyl-oxazolidineC21H41NO5Si[α]D22=+15.2 (c 1.8 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (4S,5S)

(4S,5S)-2,2-Dimethyl-N(3)-tert-butoxycarbonyl-4-tri-iso-propylsilyloxymethyl-5-hydroxymethyl-oxazolidineC21H43NO5Si[α]D22=+9.8 (c 0.8 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (4S,5S)

(4S,5S,1′S)-2,2-Dimethyl-N(3)-tert-butoxycarbonyl-4-tri-iso-propylsilyloxymethyl-5-(1′-hydroxypentadecyl)oxazolidineC35H71NO5Si[α]D22=+7.8 (c 0.5 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (4S,5S,1′R)

(4S,5S,1′R)-2,2-Dimethyl-N(3)-tert-butoxycarbonyl-4-tri-iso-propylsilyloxymethyl-5-(1′-hydroxypentadecyl)oxazolidineC35H71NO5Si[α]D22=+7.5 (c 2.8 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (4S,5S,1′R)

(4S,5S,1′S)-2,2-Dimethyl-N(3)-tert-butoxycarbonyl-4-tri-iso-propylsilyloxymethyl-5-[1′-(methanesulfonyloxy)pentadecyl]oxazolidineC36H71NO7SSi[α]D22=+6.1 (c 2.5 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (4S,5S,1′S)

(4S,5S,1′S)-2,2-Dimethyl-N(3)-tert-butoxycarbonyl-4-hydroxymethyl-5-(1′-hydroxypentadecyl)oxazolidineC26H51NO5[α]D22=+10.1 (c 2.2 in CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (4S,5S,1′S)