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|Title:||The Synthesis and Reactions of 2-Diazo-4,5-Bis(trifluoromethyl)imidazole, a Carbene Precursor to Stable Ylide and Hypervalent Compounds|
|Author(s):||Palmer, Charles Francis, Jr.|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The synthesis of 2-diazo-4,5-bis(trifluoromethyl)imidazole is discussed. An azo-linkage is used as a masked amine source in a fluorination reaction in which carboxylic acids are converted to trifluoromethyl groups. The azo compound is then hydrogenolyzed to the diazo compound precursor, 2-amino-4,5-bis(trifluoromethyl)imidazole. The diazoimidazole has a diazonium-type structure, with a short N-N bond length of 1.089 A. It may be considered as an ylide of dinitrogen.
This stable diazo compound efficiently undergoes either photochemical or thermal decomposition to give an exceptionally electrophilic carbene intermediate which will react with several elements, such as chlorine, bromine, iodine, and sulfur, which contain lone pairs of electrons to produce stable imidazolylides. The syntheses of several stable aryl halonium ylides is described. The X-ray crystal structure for a chloronium ylide prepared from this diazoimidazole is discussed. This ylide has two single bonds to the central chlorine atom with a central bond angle of 105.2$\sp\circ$.
Several reactions of the diazo compound are discussed. The diazo compound will also undergo cycloaddition reactions to give new ring systems. The use of the diazoimidazole as a hypervalent ligand is discussed.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.
|Date Available in IDEALS:||2014-12-15|