Platinum-Catalyzed Allylic C-H Alkylation with Malononitriles
Platinum-Catalyzed Allylic C-H Alkylation with Malononitriles
复制标题
铂催化的丙二腈烯丙基 C–H 烷基化
DOI：
10.31635/ccschem.021.202100884
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发表时间：
2022-01-01
期刊：
影响因子：
11.2
通讯作者：
Gong, Liu-Zhu
中科院分区：
文献类型：
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作者：
Fan, Lian-Feng;Xie, Pei-Pei;Gong, Liu-Zhu
烯丙基C-H键的直接官能化的区别在于能够从简单分子快速组装结构复杂性。虽然钯催化烯丙基C-H官能化反应已被广泛研究，但新的催化体系的发现仍然相当落后。在此，我们公开了通过使用亚磷酰胺作为配体和丙二腈作为烷基化试剂的Pt催化的广泛的α-烯烃的烯丙基C-H烷基化。值得注意的是，手性脲催化的迈克尔加成和Pt催化的烯丙基C-H烷基化的组合可以作为获得具有高水平的非对映体和对映体选择性的手性四氢吡喃的有效方案。机理研究表明，Pt催化的烯丙基C-H活化是通过一个协同的质子和双电子转移过程进行的，类似于Pd催化的过渡态几何构型.
The direct functionalization of allylic C-H bonds is distinguished by enabling rapid assembly of structural complexity from simple molecules. Although Pd-catalyzed allylic C-H functionalization has been extensively studied, the discovery of new catalytic systems remains fairly underdeveloped. Here, we disclose a Pt-catalyzed allylic C-H alkylation of a wide range of alpha-alkenes by using phosphoramidites as ligands and malononitriles as alkylating reagents. Notably, the combination of chiral ureacatalyzed Michael addition and Pt-catalyzed allylic C-H alkylation can serve as an efficient protocol to access chiral tetrahydropyran with high levels of diastereo- and enantioselectivity. Mechanistic studies suggest that the Pt-catalyzed allylic C-H activation proceeds through a concerted proton and two-electron transfer process, which is analogous to transition state geometries of Pd catalysis.