Preparation of Alkyl-Substituted Indoles in the Benzene Portion. Part 15.1 Asymmetric Synthesis of (+)-Duocarmycin SA Using Novel Procedure for Preparation of Hydroxyindoles.
作者:Hideaki MURATAKE、Naoshige MATSUMURA、Mitsutaka NATSUME
DOI:10.1248/cpb.46.559
日期:——
An asymmetric total synthesis of natural (+)-duocarmycin SA (1) starting from L-malic acid (7) was achieved as shown in Chart 5, establishing firmly the absolute configuration of 1. In order to find suitable reaction conditions for the key step, i.e., the formation of an alkoxyindole derivative, model compounds 9 and 40 were synthesized and two acetalization conditions using i) 2-ethyl-2-methyl-1,3-dioxane
如图5所示,从L-苹果酸(7)开始不完全合成天然(+)-杜卡霉素SA(1),确定了1的绝对构型。为关键化合物找到合适的反应条件步骤,即形成烷氧基吲哚衍生物,合成了模型化合物9和40,并使用i)2-乙基-2-甲基-1,3-二恶烷和三氟化硼醚化物和ii)1,3-的两个缩醛化条件发现双(三甲基甲硅烷氧基)丙烷和三氟甲磺酸三甲基甲硅烷基是有效的。先前的条件已成功应用于全合成,并从48制备了49b,收率为54%。进一步的研究包括i)将Curbius重排53b至56,以及ii)在紧邻的仲苄基存在下裂解伯苄氧基(56->