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Synfacts 2007(5): 0555-0555  
DOI: 10.1055/s-2007-968490
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

Heterogeneous Copper Catalysts for Enantioselective C-H Carbene Insertion

Contributor(s): Yasuhiro Uozumi, Tomohiko Beppu
J. M. Fraile*, J. I. García, J. A. Mayoral*, M. Roldán
Universidad de Zaragoza-C.S.I.C., Spain
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Publication History

Publication Date:
24 April 2007 (online)

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Significance

Laponite-clay-supported copper bis(oxazoline) catalyst (1-cat.) for the C-H carbene insertion reaction was prepared by cationic exchange. Methyl phenyldiazoacetate was added slowly to a hexane solution of THF in the presence of 1-cat. under reflux conditions to give 2-substituted THF in 59% yield (syn/anti = 78:22)with 88% ee (syn). In contrast to heterogeneous conditions, when conducted under homogeneous conditions the reaction gave only 48% yield (syn/anti = 64:36) with 59% ee. The 1-cat. could be recovered by filtration and reused (2nd use: 40% yield, syn/anti = 74:26, 85% ee). No leaching of copper was observed by ICP analysis after the reactions.