fluvirucins B2−B5, Sch 38518, and Sch 39185) is reported for the first time. A ring-closing metathesis (RCM) generated the C6−C7 double bond, which by catalytic hydrogenation (in toluene) gave the desired epimer with a 9:1 diastereoselection. Azide 8a and carboxylic acid 5 came from ethyl-branched fragments C9−C13 (CHO at C9) and C1−C5 via an asymmetric allylation of the former and a cross metathesis
首次报道了通向
氟维他星B 2-5(
氟维他星B 2 -B 5,Sch 38518和Sch 39185的常见糖苷配基)的途径。闭环复分解(RCM)生成了C6-C7双键,该双键通过催化氢化(在
甲苯中)以9:1的非对映体选择得到所需的差向异构体。
叠氮化物8a和
羧酸5来自乙基支化的片段C9-C13(CHO在C9)和C1-C5,它们通过前者的不对称烯丙基化和交叉易位(CM)然后是酮甲基化(含20 mol%的
DMF)作为牺牲性添加剂)。