Synthetic Applications Of Nitrenes And Synthesis Of Triazole Derivatives

Nitrenes are an important class of intermediates in organic synthesis.Although nitrenes were discovered as early as in the 19th century,their applications in organic chemistry have been less studied compared to their analogous carbenes.New reactions involving nitrene and the search for new nitrene precursors have gradually become two hot spots in chemical synthesis.This thesis describes the reactivity of 2H-azirines,anthranils,and dioxazolones and their applications in the C-N bond formation reactions.The major progress include:1.Copper(?)-catalyzed reactions of N-(alkoxy)amides and 2H-azirines were studied.The reactions afforded a-amino oxime ethers in high yields at room temperature.The reactions proceeded involving N-O and C-N bond cleavage and new C-N and N-O formation through vinyl nitrene intermediate.2.Palladium-and rhodium-catalyzed reactions of N-(acyloxy)amides and 2H-azirines were studied,and a variety of ?-amino oxime esters were regioselectively obtained in high yields.This protocol offers a simple approach to ?-amino oxime esters passes through vinyl nitrene intermediate involving the construction of new N-O bond.3.A few palladium amino complexes were prepared from PdCl2,anthranil,and iodoarenes,and their structures were determined by X-ray single-crystal diffraction.These complexes are supported by a pincer C,N,O tridentate ligand forming fused six-membered palladacycles.4.Cobalt-catalyzed reactions of triazoles and dioxazol-5-one involving acyl nitrene transfer has been described.A number of amidated 1,2,3-trizole derivatives have been obtained in moderate to excellent yields.5.A copper-mediated one-pot sequential reaction of terminal alkynes,azides,and propargylic carbonates is reported.The three component reaction occurs readily at room temperature to afford a 5-allenyl-1,2,3-triazoles in high yields,providing a straightforward approach to 1,3,5-trisubstituted triazoles using easily available Cu(?)reagent.