A total synthesis of the natural enantiomer of the title compound was accomplished, which confirmed the structure proposed for the fruitinginducing cerebroside of Schizophyllum commune. Fruiting body formation in Basidiomycetes is indeed a spectacular phenomenon especially to those who love to taste mushrooms. Its mechanism, however, is still a mystery in spite of the tremendous efforts to clarify it. Very recently Kawai and Ikeda found that the fruiting body formation of Schizophyllum conunune (Japanese name : Suéhiro také) can be stimulated by some cerebrosides in its mycelia. 2) They then identified one of the active substances as (2S,3R,4E,8E)--(2'R)-2'-hydroxyhexadecanoyl-l-~-8-D-glucopyranosyl-9-methyl-4,8_sphingadienine 3, 3) which had previously been isolated from a sea anemone (Metridium senile) by Karlsson et al. 4) Such a minute amount of &e as 0.1 ug induced the fruiting body formation of S.commune, and the corresponding ceramide ,.l& lacking the sugar portion was also active. 3) This remarkable bioactivity of & prompted us to synthesize it so as to confirm the proposed structure. 5) In this communication will be described a synthesis of the ceramide ,& with correct stereochemistry. Our synthetic & was highly active in inducing the fruiting body formation of S.commune. Construction of the sphingadienine portion of ,l& started from the known homoprenyl acetate 5. 6) Oxidation of 5 with SeO2 was followed by NaBH4 reduction to give &, whose acetylation (Ac20/C5H5N) yielded ,312 (38.0 % from 2). This was treated with n-C8H17MgBr/THF in the presente of Li2CuC14 to give & (94.2 %). The corresponding tosylate $k was submitted to the Finkelstein reaction (NaI/acetone) to afford 2 (96.2 %). Alkylation of HC'CCH20THP with 2 was effected with n-BuLi in THF/HMPA (-15", 1.5 hr; OO, 1.5 hr), yielding @ (44.3 %) after the removal of the THP group with p-TsOH/MeOH (room temp, 18 hr). The alcohol & gave an aldehyde S (92.4 %) upon treatment with Mn02 in pet ether.