Xie Rong, Mao Wenhui, Jia Huanhuan, Sun Jialu, Lu Guangpeng, Jiang Huanfeng, Zhang Min
Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology Guangzhou 510641 People's Republic of China
Chem Sci. 2021 Sep 27;12(41):13802-13808. doi: 10.1039/d1sc02967c. eCollection 2021 Oct 27.
The incorporation of a coupling step into the reduction of unsaturated systems offers a desirable way for diverse synthesis of functional molecules, but it remains to date a challenge due to the difficulty in controlling the chemoselectivity. Herein, by developing a new heterogeneous iridium catalyst composed of Ir-species (Ir ) and N-doped SiO/TiO support (Ir/N-SiO/TiO), we describe its application in reductive electrophilic mono and dialkylations of quinolines with various 2- or 4-functionalized aryl carbonyls or benzyl alcohols by utilizing renewable formic acid as the reductant. This catalytic transformation offers a practical platform for direct access to a vast range of alkyl THQs, proceeding with excellent step and atom-efficiency, good substrate scope and functional group tolerance, a reusable catalyst and abundantly available feedstocks, and generation of water and carbon dioxide as by-products. The work opens a door to further develop more useful organic transformations under heterogeneous reductive catalysis.
将偶联步骤引入不饱和体系的还原反应中，为功能分子的多样化合成提供了一种理想的方法，但由于难以控制化学选择性，迄今为止仍是一个挑战。在此，通过开发一种由铱物种（Ir）和氮掺杂的SiO/TiO载体（Ir/N-SiO/TiO）组成的新型多相铱催化剂，我们描述了其在喹啉与各种2-或4-官能化芳基羰基化合物或苄醇的还原亲电单烷基化和二烷基化反应中的应用，该反应利用可再生的甲酸作为还原剂。这种催化转化为直接获得大量烷基四氢喹啉提供了一个实用平台，该反应具有出色的步骤和原子经济性、良好的底物范围和官能团耐受性、可重复使用的催化剂以及大量可得的原料，并且副产物仅为水和二氧化碳。这项工作为在多相还原催化下进一步开发更有用的有机转化反应打开了一扇门。
