Stereoselective Synthesis of Cytotoxic Anhydrophytosphingosine Pachastrissamine [Jaspine B]
摘要:
[GRAPHICS]A practical stereoselective synthesis of cytotoxic anhydrophytosphingosine pachastrissamine (jaspine B) was achieved in 48% overall yield from D-(-)-tartaric acid. Key features of the sequence include the diastereoselective formation of a tetrol with three contiguous chiral centers, which was further elaborated to pachastrissamine. The synthetic route is operationally simple, diastereoselective and is amenable for the synthesis of a number of analogues of pachastrissamine.
Double stereodifferentiation in asymmetric dihydroxylation: application to the first diastereoselective synthesis of l-xylo-[2R,3S,4S]-C18-phytosphingosine
摘要:
The first diastereoselective synthesis of L-xylo-(2R,3S 4S)-C-18-phytosphingosine (1) has been achieved by double stereodifferentiation of enantiomerically enriched terminal olefin 14 using (DHQD(2))-PHAL ligand in an asymmetric dihydroxylation with a diastereomeric ratio of 83:17. This phytosphingosine was fully characterized by the physical and spectral data of the corresponding tetraacetate 21. (C) 2000 Elsevier Science Ltd. All rights reserved.