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
Abstract: 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.
*Lecture presented at the 11th IUPAC International
Symposium on Organometallic Chemistry Directed Towards Organic Synthesis
(OMCOS-11), Taipei, Taiwan, 22-26 July 2001. Other presentations are
presented in this issue, pp.1-186.
**Corresponding author.
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