Cobalt-Catalyzed Selective Dearomatization of Pyridines to <i>N</i>–H 1,4-Dihydropyridines
Maofu Pang, Le‐Le Shi, Yufang Xie, Tianyi Geng, Lan Liu, Rong‐Zhen Liao, Chen‐Ho Tung, Wenguang Wang
Abstract
Catalytic reduction of pyridines to N–H 1,4-dihydropyridines is exceptionally challenging because they are essential intermediates to form tetrahydropyridines. Using a facile dihydrogen source H3N·BH3 to activate the pyridine ring in situ, we have achieved selective transfer hydrogenation of nicotinate derivatives to N–H 1,4-dihydropyridines by cobalt-amido cooperative catalysis. The reactions operate smoothly under mild conditions to produce a variety of N–H 1,4-dihydropyridines with high chemo- and regioselectivity. This catalytic method also provides a practical protocol to regenerate Hantzsch analogues after delivery of H2.
Topics & Concepts
CatalysisChemistryCobaltRegioselectivityPyridineCombinatorial chemistryRing (chemistry)Medicinal chemistryOrganic chemistryAsymmetric Hydrogenation and CatalysisCatalytic C–H Functionalization MethodsChemical Synthesis and Analysis