Studies On The Selective C?H Functionalization Reactions Of 2,2'-Bipyridyl-6-Carboxamides Catalyzed By Transition Metals

The construction of C-C bonds based on transition metal-catalyzed C-H bond activation reactions is one of the most efficient tools.Compared with the traditional cross-coupling reactions,the reactions feature with atom-economic-which have been attracted significant in recent years.However,these C-H activation processes are generally incompatible with compounds have more than one chelating groups,representatively 2,2,-bipyridine(bipy)derivatives,due to the facile formation of stable bidentate or multidentate metal complexes.In addition,2,2'-bipyridyl-6-carboxamide derivatives play an important role in organic synthesis,materials science and the pharmaceutical industry.Therefore,it is highly meaningful to develop a highly efficient and selective 2,2'-bipyridyl-6-carboxamide C-H activation functionalization.This thesis mainly focuses on the research contents,which are shown as follows:1.Palladium-catalyzed selective C-H arylation of 2,2,-bipyridyl-6-carboxamide.We report the first example of C3'-arylation of 2,2'-bipyridyl-6-carboxamide via a rollover cyclometalation pathway.A diverse range of functional groups and excellent site-selectivity of this reaction were observed.The pre-rollover tridentate Pd(?)complexes were isolated and characterized to elucidate the reaction mechanism.2.Rh(?)-catalyzed C3-alkenylation of 2,2'-bipyridyl-6-carboxamide.We investigated the reactivity of a variety of 2,2'-bipyridyl-6-carboxamide substrates with triiso-propylsilylacetylene as the alkenyl source.Typically,the reaction has a good yield and exclusive regioselectivity.The common aryl alkyne is also suitable for the reaction.3.Rh(?)-catalyzed C3-acylmethylation of 2,2'-bipyridyl-6-carboxamide.A variety of simple and easily accessible sulfoxonium ylides were used as the alkyl reagents to obtain the corresponding C3-acylmethylation products up to 95%yield.The reaction featured mild conditions,extensive site-selectivity,wide substrate scope,and excellent functional group tolerance.