Li Junbao, Sun Jinghui, Ren Wenzhu, Lei Jinhua, Shen Runpu, Huang Yinhua
College of Materials, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
Zhejiang Engineering Research Center of Fat-soluble Vitamin, Shaoxing University, Shaoxing 312000, China.
Org Lett. 2022 Apr 1;24(12):2420-2424. doi: 10.1021/acs.orglett.2c00687. Epub 2022 Mar 21.
A rhodium/chiral diene catalytic system is reported for the reaction of enone-diones and arylboronic acids that allows the switchable synthesis of chiral bicyclic products and acyclic products in a controlled manner. The production of bicyclic products containing four contiguous stereocenters is assumed to proceed through the enantioselective arylrhodation of enone-diones with CsCO, forming a rhodium-enolate intermediate, followed by desymmetrization of the diastereotopic diones via aldol cyclization with quantitative diastereoselection and excellent enantiomeric excess. The production of acyclic products is assumed to proceed through the enantioselective hydroarylation of enone-diones with excellent enantiomeric excess in which the aldol cyclization is significantly inhibited by the choice of EtN as a base. The selectivity for bicyclic products (via tandem arylation-aldol cyclization) and acyclic products (via hydroarylation) is rationalized by the proposed model.
据报道，一种铑/手性二烯催化体系可用于烯二酮与芳基硼酸的反应，该体系能够以可控方式实现手性双环产物和非环产物的可切换合成。含有四个相邻立体中心的双环产物的生成被认为是通过烯二酮与碳酸铯进行对映选择性芳基铑化反应，形成铑烯醇盐中间体，然后通过醛醇缩合环化使非对映异位二酮去对称化，实现定量的非对映选择性和优异的对映体过量。非环产物的生成被认为是通过烯二酮的对映选择性氢芳基化反应，具有优异的对映体过量，其中通过选择乙腈作为碱可显著抑制醛醇缩合环化反应。所提出的模型解释了双环产物（通过串联芳基化 - 醛醇缩合环化）和非环产物（通过氢芳基化）的选择性。
