Photoinduced direct 4-pyridination of C(sp3)–H Bonds
作者:Tamaki Hoshikawa、Masayuki Inoue
DOI:10.1039/c3sc51080h
日期:——
Direct substitution of hydrogen in C(sp3)âH bonds by 4-pyridine was achieved by employing benzophenone and 4-cyanopyridine in aqueous acetonitrile under photo-irradiating conditions. This simple and mild 4-pyridination proceeds in a highly chemoselective manner especially at benzylic C(sp3)âH bonds without affecting polar functional groups, and enables intermolecular formation of sterically hindered bonds between alkylaromatics and 4-pyridine. The present methodology thus serves as a powerful tool for construction of biologically active and functional molecules with 4-pyridine substructures.
Lewis Acid-Catalyzed Selective Reductive Decarboxylative Pyridylation of <i>N</i>-Hydroxyphthalimide Esters: Synthesis of Congested Pyridine-Substituted Quaternary Carbons
作者:Liuzhou Gao、Guoqiang Wang、Jia Cao、Hui Chen、Yuming Gu、Xueting Liu、Xu Cheng、Jing Ma、Shuhua Li
DOI:10.1021/acscatal.9b03798
日期:2019.11.1
practical and efficient Lewis acid-catalyzed radical–radical coupling reaction of N-hydroxyphthalimide esters and 4-cyanopyridines with inexpensive bis(pinacolato)diboron as reductant has been developed. With ZnCl2 as the catalyst, a wide range of quaternary 4-substituted pyridines, including highly congested diarylmethyl and triarylmethyl substituents, could be selectively obtained in moderate to good