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Pure Appl. Chem., 2002, Vol. 74, No. 1, pp. 143-149

Metal-assisted amination with oxime derivatives

Koichi Narasaka

Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

Electrophilic amination of Grignard reagents is accomplished by using O-sulfonyl-oximes of benzophenone derivatives. In the presence of a catalytic amount of CuCN, O-sulfonyloxime of 4,4¢-bis(trifluoromethyl)benzophenone reacts with alkyl Grignard reagents in tetrahydrofuran (THF) and hexamethylphosphoramide (HMPA), yielding primary alkyl-amines by successive hydrolysis of the resulting N-alkylimines. Arylamines are also prepared as well as alkylamines by treating O-sulfonyloxime of 3,3¢,5,5¢-tetrakis(trifluoromethyl)benzophenone in toluene-ether with Grignard reagents.
Various cyclic imines are synthesized by palladium-catalyzed cyclization of olefinic oxime derivatives. That is, the reaction of O-pentafluorobenzoyloximes of olefinic ketones with a catalytic amount of Pd(PPh3)4 and triethylamine in dimethylformamide (DMF) affords nitrogen-containing heterocycles, such as pyrroles, pyridines, isoquinolines, spiro-imines, and aza-azulenes. This reaction proceeds via the initial formation of alkylideneaminopalladium species generated by oxidative addition of oximes to Pd(0), and the successive intramolecular Heck-type amination occurs on the olefinic moiety.