“…4) The key compound in the synthesis of (ϩ)-1 and (ϩ)-3 is (4R,5S)-4-benzyloxy-5-silyloxy-2(E)-hexenoic acid 7 and this compound was also used for the synthesis of 2 or 4 as a starting material. Condensation of carboxylic acid (4R,5S)-7 and commercially available (3R)-hydroxy butanoate 8 via the Keck procedure 5) MS) of (3R,8R,9S,14R,15S))-2 and (3S,8R,9S,14R,15S)-4 quite resembled those of the natural product 2, respectively, while both retention times of (3R,8R,9S,14R,15S)-2 (t R ϭ19.3 min) and (3S,8R,9S,14R, 15S)-4 (t R ϭ25.8 min) by mean of HPLC (column; CHIRAL-CEL OD (0.46ϫ25 cm), solvent; n-hexane-EtOH (10 : 1); detection; 254 nm) were quite different. The retention time of (3R,8R,9S,14R,15S)-2 was found to be consistent with that (t R ϭ19.3 min) of the natural product 2.…”