Study On The Synthesis Of α-amino Ketones By O-H Insersion-rearrangement Reaction Of α-amino Rhodium Carbene

1,2,3-Triazole is an important heterocycle with important biological activities.On the other hand,it can be used as an useful precursor of carbene,which can be converted into metal carbene under the catalysis of transition metals such as Rh,Au,Cu,Pd and Fe.Metal carbene can be used as a kind of very important synthetic intermediate to carry out a series of chemical transformations and play a vital role in organic synthesis.After more than ten years of development,α-imino carbene has become one of the indispensable tools in organic synthesis.Among them,reaction of rhodium catalyzed N-sulfonyl-1,2,3-triazole to generateα-imino rhodium carbene due to the low dosage of catalyst and high reaction efficiency advantages have been widely reported in X-H（C-H,O-H and N-H）insertion reaction,rearrangement reaction,etc.Such reactions have been widely used in organic synthesis because of their efficiency and convenience in synthesis of various novel nitrogen-containing compounds.In this thesis,rhodium-catalyzed intermolecular and intramolecular O-H insertion-rearrangement reactions of N-sulfonyl-1,2,3-triazole were studied,and chain and annularα-aminoketones were synthesized:（1）Rhodium catalyzed intermolecular O-H insertion-rearrangement reaction of N-sulfonyl-1,2,3-triazole with benzoquinone derived alcohols producesα-amino ketone.By optimizing the reaction conditions,the target compound was obtained via the reaction of 2 equivalent N-sulfonyl-1,2,3-triazoles with benzoquinone derived alcohols at medium to excellent yield using 0.5 mol%Rh₂（piv）₄ as catalyst,chloroform as solvent at reflux（70 ^oC）under nitrogen atmosphere.The reaction conditions are mild and has good functional group compatibility.The products can be further converted into oxazinone and benzofuran products,which expands the application of N-sulfonyl-1,2,3-triazoles in heterocyclic synthesis.（2）Under rhodium catalysis,2-aryl-1-（N-sulfonyl-1,2,3-triazole）-2-ol was synthesized by intramolecular O-H insertion and rearrangement reaction to formα-aminocyclobutanone.From the optimal conditions were as follows:2-aryl-1-（N-sulfonyl-1,2,3-triazolium）-2-ol heated at 60 ^oC using 3 mol%Rh₂（piv）₄ as catalyst,1,2-dichloroethane as solvent under nitrogen atmosphere.The reaction conditions are mild and the functional group compatibility is good.High diastereoselectivity can be achieved by adjusting the substituents,which provides a mild and efficient new strategy for the synthesis of multi-substituted 4-membered cyclic compounds.