The Research On Dehydrogenation/hydrogen Transfer Coupling Reaction Of Six-membered Nitrogen Heterocyclic

It's very important to construct the skeleton of six-membered N-heterocyclic or derivate it,which widely existed in bioactive natural products,organic materials,agricultural agents,and medicine.On the other hand,dehydrogenative coupling and hydrogen transfer coupling reaction were basic and important process in the organic catalytic transformations.Recently,catalytic dehydrogenative coupling and hydrogen transfer coupling reaction has became one of highlights in scientific research.Based on study on N-heterocyclic in our group and current research background of oxidative coupling as well as transfer hydrogen coupling,this paper mainly studied on catalytic dehydrogenative coupling and hydrogen transfer coupling reaction of the six-membered N-heterocyclic.This thesis is mainly divided into the following three parts:In the firsrt part,we developed a new benzylation protocol,enabling straightforward access to beta-benzylated quinolines.By employing readily available [RuCl2(p-cymene)]2 as a catalyst and O2 as a sole green oxidant,various 1,2,3,4-tetrahydroquinolines were efficiently converted in combination with aryl aldehydes into desired products in a step-and atomeconomic fashion together with the advantages of excellent functional group tolerance and chemoselectivity.Mechanistic investigations support that the reaction undergoes a monodehydrogenation-triggered beta-benzylation mode.In the second part,we introduced a novel iridium/acid co-catalysed transfer hydrogenative coupling strategy,enabling direct alkylation of C(sp3)-H bonds and atomeconomic access to alkyl chain-lengthened N-heteroaromatics from six-membered 2-alkyl cyclic amines and aldehydes.This work has built an important basis to convert cyclic amines,a class of bulk chemical raw materials,into functionalized products.In the last part,a new aerobic copper-catalyzed halocyclization reaction of methyl Nheteroaromatics and aliphatic amines has been developed,which enables straightforward access to functionalized imidazo-fused N-heterocycles with the merits of good functional tolerance,use of easily available copper salts as the catalysts,lithium halides as the halogen sources,and O2 as a sole oxidant.Due to the reaction features' selective introduction of halogen functionalities to the newly formed imidazo ring,further extensions of the developed chemistry toward synthetic diversity,including effective access to functional materials,are easily envisioned.