Studies On The Application Of Diazo Compounds As Efficient N-Terminal Electrophiles In Organic Synthesis

Diazo compounds,as an important class of organic synthesis intermediates,play a vital role in organic synthesis.They are widely used in the synthesis of natural products,drug molecules,material molecules and other complex compounds.Due to the existence of various resonance forms,the diazo compounds not only have unique and diverse chemical properties,but also have high reactivity.At present,most researches on the application of diazo compounds are focused on the use of diazonium compounds as carbene precursors,1,3-dipoles and carbon nucleophiles,but the utility of the electrophilic capability of their terminal nitrogen was rarely studied.In this paper,the diazo compounds are used as the effective N-terminal electrophiles as the core.In the condition of alkaline,a nucleophilic addition reaction of a plurality of sp~2hybrid aryl carbons,activated and inert sp~3 hybrid carbon nucleophiles to the nitrogen atom of the diazo compound is achieved.On this basis,combined with the introduction of functional groups and transformation strategies,a variety of guided synthesis were achieved to prepare a series of chain and cyclic nitrogen-containing compounds with important application value.And a Rh(I)catalyzed coupling-cyclization reaction of alkenyldiazoacetates with o-alkenyl arylisocyanides has been developed.The specific research content is as follows:1.Promoted by t~BuLi,the nucleophilic addition reaction of various aryl compounds to the nitrogen of the diazo compound was carried out with various aryl compounds as carbon nucleophiles.This reaction not only provides an efficient strategy for the formation of aromatic C-N bonds but also synthesizes a variety of aryl and porphyrin derivatives and represents a simple and efficient method for dearomatization reaction for hydrazine derivatives.2.With the diazo compound as the effective N-terminal electrophiles as the core,under the catalysis of DBU,a nucleophilic addition reaction of an activated sp~3 hybridized carbon nucleophile containing a basic structure of an imine to a N-terminal of a carbonyl diazo compound has been developed.On this basis,combining the structural functional group regulation,conversion and oxidation strategies,through the continuous intermolecular nucleophilic addition,intramolecular Michael addition and oxidative aromatization reaction process,successfully prepared a variety of tetrahydro/dihydrotriazine,triazines and1,2,4-triazole derivatives.3.With the diazo compound as the effective N-terminal electrophiles as the core,under the action of ~nBuLi,the inert sp~3 hybridized benzyl carbon was used to carry out the nucleophilic addition reaction with the diazo compound terminal nitrogen.Using the methyl group of azacyclobenzyl or methyl sulfide as a carbon nucleophile,the nucleophilic addition of one molecule or two molecules of carbon nucleophile to the terminal nitrogen of the diazo compound is carried out respectively,preparing a series of N-alkyl hydrazones and providing a new method for constructing benzyl and alkyl sulfides C(sp~3)-N bonds.4.We use simple alkenyl diazoacetates and o-alkenyl aryl isonitrile as substrates,under the catalysis of rhodium,using the ketenimine as the reaction intermediates undergoing the intramolecular[4+2]cycloaddition to preparing a series polysubstituted oxazoles.The reaction is not only simple and efficient,but also constructs three chemical bonds and two aromatic ring systems in one step,and provides a new method for directly constructing carbazole compounds from a chain compound in one step.In addition,the realization of this reaction also lays a foundation for further application of coupling reaction with functionalized diazo compounds and isonitrile compounds in organic synthesis.