1. Carbene reactivity of 4-diazo-4H-imidazoles toward nucleophiles and aromatic compounds.
- Author
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Smith MR, Blake AJ, Hayes CJ, Stevens MF, and Moody CJ
- Subjects
- Alcohols chemistry, Amines chemistry, Antineoplastic Agents chemistry, Cyclization, Fluorocarbons chemistry, Hydrogen chemistry, Methane chemistry, Nitrogen chemistry, Oxygen chemistry, Photochemistry, Pyridines chemistry, Solvents chemistry, Temperature, Azo Compounds chemistry, Hydrocarbons, Aromatic chemistry, Imidazoles chemistry, Methane analogs & derivatives
- Abstract
Carbenes derived from diazoimidazolecarboxylates 4 under thermal or photochemical conditions undergo O-H and N-H insertion reactions with alcohols and amines, respectively, in moderate yield, in competition with reduction in good H-donor solvents. Dichloromethane reacts to give the corresponding 4-chloroimidazole. Aromatic hydrocarbons are excellent traps for the imidazolylidene carbene and lead to a range of arylimidazole derivatives 7. Reaction with pyridine leads to the first example of a pyridinium ylide 8 formed from an imidazolylidene carbene, whereas irradiation in hexafluorobenzene gives the imidazoazocine 11, presumably by way of an initial norcaradiene intermediate.
- Published
- 2009
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