Asymmetric synthesis of D-ribo-phytosphingosine from 1-tetradecyne and (4-methoxyphenoxy)acetaldehyde.
An asymmetric synthesis of d-ribo-phytosphingosine (1) was achieved by utilizing the ProPhenol (12)-catalyzed alkynylation of unsaturated aldehyde 8 to afford allylic propargylic alcohol (S)-6 followed by asymmetric epoxidation and opening of propargylic epoxy alcohol anti-5 with NaN(3)/NH(4)Cl. Deprotection and reduction of the resulting acyclic azide 3 then gave 1. Alkyne-azide 3 was subjected to an intramolecular click reaction, generating a bicyclic triazole, which was found to have unexpected vicinal coupling constants. Application of the advanced Mosher method verified the configurations of the three contiguous stereogenic centers of 1. An alkynyl azide analogue of 1, which may be useful as a glycosyl acceptor in the synthesis of alpha-galactosylceramide derivatives, was also readily prepared by this route.
Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing, New York 11367-1597, USA.
Zheng
Z
Liu
Hoe-Sup
HS
Byun
Robert
R
Bittman
D000079:Acetaldehyde / Q000737:chemistry*; D000478:Alkylation; D000480:Alkynes / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D002384:Catalysis; D005699:Galactosylceramides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism
D000480:Alkynes; D001386:Azides; C521790:D-ribo-phytosphingosine; D005699:Galactosylceramides; D000079:Acetaldehyde; D013110:Sphingosine