Studies On Silver Carbenoids Base On Low-Temperature Decomposable N-sulfonylhydrazones

The chemistry of diazo compounds was discovered a century ago,and even today remained as an active field in organic synthesis.Diazo compounds have been widely explored as a source of carbenoids and also served as 1,3-dipoles and nucleophiles in the construction of various nitrogen-containing functional molecules.However,the utility of diazo compounds is significantly limited by their toxicity,instability and unpredictable explosive behavior.Thus,there has been considerable interest in the development of reliable diazo precursors from readily available starting materials.Among them,N-tosylhydrazones are superior surrogates duo to their safety,stability and easy availability from carbonyl compounds.In the past decade,a rapid progress in this field has been witnessed by numerous novel transformations such as cross-coupling reaction,rearrangement,ring-expandation,and C-H functionalization.However,the high temperature(70-110 ℃)required for their dissociation into diazo species severely challenges their utilization in the synthetic areas which disfavoring high temperature.Very recently,we have discovered the potential of N-nosylhydrazones as room-temperature decomposable diazo surrogates,which offer new synthetic opportunities to the utility of non-stabilized diazo compounds,such as aryl-,alkenyl-,and alkynyldiazomethanes.As part of our continued interest in silver-catalyzed transformations,my thesis focused on silver-catalyzed carbene transfer reactions by using N-nosylhydrazones as the carbene precursors.The details are summarized as following:(1)Studies on silver-catalyzed [2+1] cycloaddition reaction: we have developed a general and powerful [2+1] cycloaddition reaction of alkynes and sterically hindered 1,2-diarylalkenes with non-stabilized diazo compounds,by for the first time the discovery and application of N-nosylhydrazones as room-temperature decomposable diazo surrogates.(2)Studies on the one-carbon insertion of diazo compounds into C–C or C-H bonds of 1,3-dicarbonyls: a catalyst-controled chemoselective one-carbon insertion of diazo compounds into the C–C or C-H bonds of 1,3-dicarbonyls is described.(3)Silver-catalyzed cross-olefination of donor and acceptor diazo compounds: the silver-catalyzed cross-olefination reaction of donor and acceptor diazo compounds is achieved by using N-nosylhydrazones as the donor-diazo compounds precursors.