The synthesis of functionalized GEM-dinitrocyclopropanes via [3+2] cycloaddition of diazocarbonylcompounds with 1,1-dinitroethenes [in some cases in the presence of Mo(CO) 6 as catalyst] has been developed.
The one-pot synthesis of multisubstituted pyrazole derivatives was achieved viacatalyst-free 1,3-dipolar cycloaddition of ethyl diazoacetate and nitroalkenes as the key step and elimination of the leaving group (NO2 or Br) followed by intramolecular proton transfer with satisfactory yields.