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DOI: 10.1055/s-2007-968479
Raney Cobalt Catalyzed Pauson-Khand Reaction
Contributor(s):Yasuhiro Uozumi, Yoichi M. A. YamadaRWTH Aachen and Max Planck Institute of Coal Research, Mülheim an der Ruhr, Germany
Raney Cobalt: An Effective and Recyclable Catalyst for the Pauson-Khand Reaction
Adv. Synth. Catal. 2007, 349: 287-291
Publication History
Publication Date:
24 April 2007 (online)
Key words
Raney cobalt - Pauson-Khand reaction - cyclopentenones - leaching
Significance
Commercially available Raney cobalt was applied to the intra- and intermolecular Pauson-Khand reaction. Thus, the reaction of 1a was performed with Raney cobalt under CO atmosphere in THF to give 2a in 94.5% conversion with 96.8% selectivity. The catalyst was reused five times with a slight loss of catalytic activity. Seven examples of the Pauson-Khand reaction were examined under similar conditions [Raney cobalt (6-16 mol%), CO (23-35 bar)] to afford cyclopentenones 2a-g with 54.2-99.5% conversion and 91.5-98.0% selectivity.
Comment
The activity of Raney cobalt compared favorably with that of previously reported heterogeneous cobalt-catalyzed systems where 15-20 mol% of catalysts were used. The reaction appeared to occur mainly at the solid catalyst although small amounts of active species were present in the reaction solution.