Xu Jianyou, Cheng Tanyu, Zhang Kun, Wang Ziyun, Liu Guohua
Laboratory of Resource Chemistry of Ministry of Education, Shanghai Normal University, Shanghai 200234, China.
Chem Commun (Camb). 2016 May 1;52(35):6005-8. doi: 10.1039/c6cc00590j. Epub 2016 Apr 11.
Construction of a site-isolated heterogeneous catalyst to realize the compatibility of bimetallic complexes for a feasible tandem reaction is a significant challenge in heterogeneous asymmetric catalysis. Herein, taking advantage of yolk-shell-structured mesoporous silica, we assemble an active site-isolated bifunctional catalyst through assembly of organopalladium-functionality into silicate channels as an outer shell and chiral organoruthenium-functionality onto silicate yolk as an inner core, realizing the one-pot enantioselective tandem reaction from Pd-catalyzed Sonogashira coupling to Ru-catalyzed asymmetric transfer hydrogenation. As presented in this study, this tandem Sonogashira coupling-asymmetric transfer hydrogenation of haloacetophenones and arylacetylenes affords various chiral conjugated alkynols with high yields and up to 99% enantioselectivity. Moreover, a catalyst can also be recovered easily and recycled repeatedly, making it an interesting feature in a practical organic transformation.
构建一种位点隔离的多相催化剂以实现双金属配合物在可行串联反应中的兼容性，是多相不对称催化领域的一项重大挑战。在此，我们利用蛋黄壳结构的介孔二氧化硅，通过将有机钯功能基团组装到作为外壳的硅酸盐通道中，以及将手性有机钌功能基团组装到作为内核的硅酸盐蛋黄上，组装了一种活性位点隔离的双功能催化剂，实现了从钯催化的Sonogashira偶联到钌催化的不对称转移氢化的一锅法对映选择性串联反应。如本研究所示，这种卤代苯乙酮和芳基乙炔的串联Sonogashira偶联 - 不对称转移氢化反应能够以高收率和高达99%的对映选择性得到各种手性共轭炔醇。此外，催化剂还能够轻松回收并重复使用，这使其在实际有机转化中具有吸引人的特性。
