Studies On Copper-catalyzed Cross-coupling Reaction Of Diazo Compounds And [3+2] Cycloaddition Reaction Of ?,?-unsaturated Sulfimides With N-tosylhydrazones

The substituted pyrazoles are widely found in many biologically active compounds as an important core structures,including pharmaceuticals,protein ligands and natural products.Lots of approaches have been developed for the preparation of pyrazoles in the past few years.It chiefly aims at introducing some published examples with regard to the synthetic pyrazoles by transition-metal(metal-free)catalytic cyclization of diazo or hydrazine.In the second part,copper-catalyzed cross-coupling reaction of of unstable diazo compounds under mild reaction conditions providing N-sec-alkylated pyrazole derivatives,has been developed.We optimize the reaction conditions for the cross-coupling reaction using the cinnamaldehyde and acetophenone as model substrates.The operational simplicity of the process tolerate different functions group.Various aldehyde and ketones were compatibled affording the corresponding N-substituted pyrazoles in excellent enantioselectivities(4:1-20:1 dr)and good yields(80%-99%).A new method to construct N-substituted pyrazole compounds has been developed.In the third part,a new metal-free [3+2] cycloaddition reaction of ?,?-unsaturated sulfonylamide with N-tosylhydrazones providing N-aminopyrrole has been developed.Under the optimal condition,a wide range of substitution patterns at the ?,?-unsaturated sulfonylamides and N-tosylhydrazones were nicely tolerated to the reaction,providing the corresponding N-aminopyrrole in good to high yields.A simple method for the synthesis of N-aminopyrrole was developed.