Studies Of Transition-Metal Catalyzed C-H Bond Activation Of Nitrogen-Containing Compounds

Transition-metal catalyzed C-H activation assited by directing group has become a powerful and efficient strategy to construct carbon-carbon/carbon-hetero bonds and heterocycle synthesis due to its step-economical manner and atom-economic advantages.Nitrogen-containing are important organic compounds which widely exist in nutral products,medicine and materials.Therefore,development of tranision-metal catalyzed C-H activation assisted by nitrogen-containing directing group is highly desirable.This manuscript mainly focused on the transition metal-catalyzed C-H bond functionalization of different nitrogen-containing directing group.The contents were listed as follows:1.Synthesis of Quinoline N-Oxides by Cobalt-Catalyzed Annulation of Arylnitrones and AlkynesQuinoline N-oxides constitute an important class of compounds.Traditional approaches to quinoline N-oxides generally require an additional oxidation of quinoline by using strong oxidant such as H2O2,m-CPBA,leading to poor compatability of substrates and functional groups.Development of new and efficient methods to access to quinoline N-oxides is highly desirable.We successfully realized cobalt-catalyzed annulation of arylnitrones and alkynes to obtain multi substituted quinoline N-oxides.The reaction showed good functional group tolerance and high regioselectivity.Screening of different nitrones revealed that the installation of 2,6-dichloorophenyl ring in the substrate has a huge effect on the transformation.DFT study reveal that installation of 2,6-dichloorophenyl ring could reduce the activation energy.2.Mn(?)-Mediated Phosphorylation of Enamides Under Room TemperaturePhosphorus compounds are important organic compounds which are not only an indispensable material for maintaining the normal operation of living organisms but also widely used in pesticides,materials and ligands.C-P bond formation has drawn broad attention.Direct C-P bond formation between C-H and P-H bond coupling has become the one of most efficient strategy due to atom-economic advantages.A highlyZ-selective phosphorylation to access ?-phosphorylated enamides via Mn(?)-mediated cross-dehydrogenative-coupling of enamides with phosphine oxide has been developed under mild reactions.The reaction showed good broad substrate scope.The products could be further reduced and hydrolyzed to?-aminophosphine.Therefore,we have developed an indirect method for the synthesis of ?-aminophosphine.DFT study reveal that intramolecular hydrogen bond might play the role in the highselectivitv.3.Rh(?)-catalyzed Annulation of Imidates and Nitroalkenes to Access to?-Aminonitroalkenes?-Aminonitroalkenes are important compound which could be easily converted to a-amino acids and 1,2-diamine.They also are widely used as building blocks for the heterocycle synthesis.Traditional methods to synthese ?-aminonitroalkenes consist of multistep processes,and the post-treament is troublesome.Development of new and efficient methods to obtain ?-aminonitroalkenes is highly desirable.Herein,we reported a Rh(?)-catalyzed annulation of imidates and nitroalkenes to access to?-Aminonitroalkenes.The reaction showed broad substrate scope and good functional group tolerance.