(-)-erythronolide B (5) 及其两种 9-二氢衍生物(52 和 54)来自 (R)-2,3-O-异亚丙基甘油醛 (20) 的收敛全合成(最长线性路线上的 22 步)作为手性的唯一来源被描述。A key step of the synthesis is the regio- and stereocontrolled coupling of the allyl sulfide anion 39 and ketone 26 which can be directed to either α-adduct 40 or 41 by an appropriate choice of the conditions (Scheme V, table II). 由40和41制备seco酸47和49,根据改进的Yamaguchi程序将其顺利地大环内酯化为50和51。在大环立体控制下进行 50
(-)-erythronolide B (5) 及其两种 9-二氢衍生物(52 和 54)来自 (R)-2,3-O-异亚丙基甘油醛 (20) 的收敛全合成(最长线性路线上的 22 步)作为手性的唯一来源被描述。A key step of the synthesis is the regio- and stereocontrolled coupling of the allyl sulfide anion 39 and ketone 26 which can be directed to either α-adduct 40 or 41 by an appropriate choice of the conditions (Scheme V, table II). 由40和41制备seco酸47和49,根据改进的Yamaguchi程序将其顺利地大环内酯化为50和51。在大环立体控制下进行 50
The firsttotalsynthesis of onchitriolII, a cytotoxic metabolite of mollusc Onchidium sp., is described. It employs mild cyclization method [DMSO - (COCl)2 or Ph3P - CCl4] of triketides bearing optically active functional groups to the corresponding γ-pyrones as a key step. Additional synthesis of some diastereoisomers provided a possibility to revise the structure of closely related onchitriol I.