67(P1-15) D-erythro-C_<18>-スフィンゴシン誘導体の合成(ポスター発表の部)  [in Japanese] 67(P1-15) SYNTHESIS OF D-erythro-C_<18>-SPHINGOSINE DERIVATIVES  [in Japanese]

As a part of our synthetic studies on complex carbohydrate, we wish to describe here the convenient and practical synthesis of D-erythro-C_<18> -sphingosine(2), an essential constituent of sphingoglycolilids, from the derivative of L-Serine. First, we studied the Horner-Wittig reaction of L-serylmethylphosphonate and found N-t-butoxycarbonyl-N, O-isopropylidene-L-serylmethylphosphonate(7) was suitable for this purpose. Phosphonate 7 was reacted with tetradecanal in the presence of caesium carbonate in isopropyl alcohol to afford the corresponding (E)-olefin 8 in 86% yield selectively. Next, we tried the stereoselective reduction of carbonyl group in (E)-olefin 8 and found the reaction using NaBH_4-CeCl_3 in tetrahydrofuran-methanol at room temperature gave the desired D-erythro-C_<18>-sphingosine derivative 9 in 90% yield with high stereoselectivity (erythro:threo=5:1). Because the synthesis of 2 from 9 have been reported, the formal synthesis of 2 was completed. Further, it is expected that compoud 9 can be converted easily to the glycosyl acceptor for the synthesis of sphingoglycolipids.