抄録
The structures of many interesting Sphingoglycolipids from marine organisms have been determined. Although their biological functions are still not clear, these compounds are assumed to participate in various processes associated with recognition phenomena. We report here the stereoselective syntheses of the sphingosine 3 of 1, isolated from a marine snail Turbo cornutus, and the ceramide parts 12 and 21 of 2, isolated from a marine sponge Halichondria japonica. D-Erythro-C_<18>-sphingosine 3 was prepared from 3,4,6-tribenzyloxygalactal 4 in nine steps in 26% overall yield. Highly optically pure long-chain (R)- and (S)-α-hydroxy acids 20a and 20b were prepared via nucleophilic ring opening of chiral epoxy diols 15 and 16, respectively, which are derived from L-ascorbic acid. The attempt towards the total synthesis of phytosphyngosine part 21 of 2 from the same key intermediate 15 is described.
