Gudipati Venugopal, Curran Dennis P, Wilcox Craig S
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
J Org Chem. 2006 Apr 28;71(9):3599-607. doi: 10.1021/jo060217x.
The principles of the oligoethylene glycol (OEG) mixture synthesis are illustrated with the synthesis of all four possible stereoisomers of a hydroxybutenolide fragment common to murisolin and many other acetogenins. Modified dimethoxybenzyl groups with varying numbers of OEG units (-CH2CH2O-) are used to protect alcohols and serve as codes for configurations at two stereocenters. The encoded isomers are carried through several steps in a sequence of mixing prior to the reaction and then demixing during the separation to give individual pure products. A new tagging scheme is introduced in which a stereocenter bearing a hydroxy group is given two different tags. These initially redundant tags then serve to encode the configuration of another (untagged) stereocenter by appropriate pairwise reactions of the tagged precursors. The experimental features (reaction, analysis, separation, and characterization) of OEG mixture synthesis are detailed and are compared to and contrasted with those of fluorous mixture synthesis.
通过合成鼠李素和许多其他产乙酸素中常见的羟基丁烯内酯片段的所有四种可能的立体异构体，阐述了低聚乙二醇（OEG）混合物合成的原理。带有不同数量OEG单元（-CH2CH2O-）的修饰二甲氧基苄基用于保护醇类，并作为两个立体中心构型的编码。编码的异构体在反应前的混合序列中经过几个步骤，然后在分离过程中进行反混合，以得到单个纯产物。引入了一种新的标记方案，其中带有羟基的立体中心被赋予两个不同的标记。这些最初冗余的标记随后通过标记前体的适当成对反应来编码另一个（未标记）立体中心的构型。详细介绍了OEG混合物合成的实验特征（反应、分析、分离和表征），并与氟混合物合成的特征进行了比较和对比。
