Herber Christian, Breit Bernhard
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
Chemistry. 2006 Aug 25;12(25):6684-91. doi: 10.1002/chem.200600343.
A new iterative strategy for the flexible preparation of any oligodeoxypropionate stereoisomer is presented which relies on an o-DPPB-directed copper mediated allylic substitution employing enantiomerically pure Grignard reagents; the reaction is working with perfect control over all aspects of the reaction selectivity. This key C--C bond-forming step features reversed polarity compared with established enolate alkylation methodology. It thus avoids existing problems of enolate alkylation strategies such as enolate reactivity as well as costs and problems associated with the chiral auxiliary. Practicability of this new method is demonstrated through application in natural product syntheses. Thus, an efficient synthesis of the northern part of the angiogenesis inhibitor borrelidin (28), the deoxypropionate building block 27, could be devised, representing a formal total synthesis.
本文提出了一种灵活制备任何寡脱氧丙酸酯立体异构体的新迭代策略，该策略依赖于邻二苯基膦硼烷（o-DPPB）导向的铜介导烯丙基取代反应，使用对映体纯的格氏试剂；该反应在反应选择性的各个方面都能完美控制。与已有的烯醇盐烷基化方法相比，这一关键的碳-碳键形成步骤具有相反的极性。因此，它避免了烯醇盐烷基化策略中存在的问题，如烯醇盐反应性以及与手性助剂相关的成本和问题。通过在天然产物合成中的应用，证明了这种新方法的实用性。因此，可以设计出一种高效合成血管生成抑制剂硼雷素（28）北部部分、脱氧丙酸酯结构单元27的方法，这代表了一种形式上的全合成。
