C(sp3)-H dehydrogenation and C(sp2)-H alkoxy carbonylation of inactivated cyclic amines towards functionalized N-heterocycles.
A novel and efficient synthesis of tetrahydropyridine (THP)-, dihydropyrrole (DHP)-, or tetrahydroazepine (THA)-3-carboxylates via cascade reactions of inactivated cyclic amines with CO and alcohols is presented. To our knowledge, this should be the first example in which functionalized N-heterocycles were prepared directly from Pd-catalyzed C(sp3)-H dehydrogenation and C(sp2)-H carbonylation of saturated cyclic amines. Moreover, the DHP-3-carboxylates thus obtained could readily undergo an oxidative aromatization to give pyrrole-3-carboxylates by using O2as a green oxidant. Notable features of the methods developed herein include simple substrates, high efficiency and excellent atom-economy, mild reaction conditions, and broad substrate scope.
School of Chemistry and Chemical Engineering, School of Environment, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China. heyan@htu.cn xuesen.fan@htu.cn.
Yan
Y
He
School of Chemistry and Chemical Engineering, School of Environment, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China. heyan@htu.cn xuesen.fan@htu.cn.
Fang
F
Wang
School of Chemistry and Chemical Engineering, School of Environment, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China. heyan@htu.cn xuesen.fan@htu.cn.
Xinying
X
Zhang
School of Chemistry and Chemical Engineering, School of Environment, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China. heyan@htu.cn xuesen.fan@htu.cn.
Xuesen
http://orcid.org/0000-0002-2040-6919
X
Fan