An Improved Synthesis of Procyanidin Dimers: Regio- and Stereocontrol of the Interflavan Bond
作者:Isabelle Tarascou、Karine Barathieu、Yann André、Isabelle Pianet、Erick J. Dufourc、Eric Fouquet
DOI:10.1002/ejoc.200600668
日期:2006.12
A direct and general synthesis of procyanidin dimers B1, B2, B3 and B4 (10a–d) is presented. The approach is based on the stoichiometric coupling of two protected monomeric units (the nucleophilic 2a–b and electrophilic 4a–b partners) and deals with the regio- and stereocontrol of the C4–C8 interflavan bond as well as the control of the degree of oligomerization. The synthesis involves a five-step
介绍了原花青素二聚体 B1、B2、B3 和 B4 (10a-d) 的直接和一般合成。该方法基于两个受保护单体单元(亲核 2a-b 和亲电 4a-b 伙伴)的化学计量偶联,并处理 C4-C8 间黄烷键的区域和立体控制以及控制程度低聚。合成涉及从天然儿茶素 (1a) 或表儿茶素 (1b) 开始到完全脱保护的二聚体 10a-d 的五步途径。此外,该过程似乎是迭代的,因为偶联中间体 9a-d 本身可以很容易地用于三聚体或更高级低聚物的进一步选择性合成。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)