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Synfacts 2009(7): 0805-0805
DOI: 10.1055/s-0029-1217231
DOI: 10.1055/s-0029-1217231
Polymer-Supported Synthesis
© Georg Thieme Verlag
Stuttgart ˙ New York
Well-Defined Silica-Supported Olefin Metathesis Catalysts
D. P. Allen, M. M Van Wingerden, R. H. Grubbs*
California Institute of Technology, Pasadena, USA
Further Information
Publication History
Publication Date:
22 June 2009 (online)
Significance
Silica-supported N-heterocyclic carbene (NHC) ruthenium complexes were developed as immobilized metathesis catalysts. Thus, for example, allylation of bisimine 1 and subsequent reduction with NaBH4 gave diamine 2 which was treated with HCl and HC(OEt)3 to afford the imidazolium chloride 3. Pt(0)-catalyzed hydrosilylation of 3 using HSiCl3 followed by EtOH/Et3N treatment gave the NHC salt 4. Ruthenium complex 5 was prepared by deprotonation of 4 with KHMDS and treatment of the resulting free carbene with ruthenium complex 7. Ruthenium complex 5 was anchored to silica gel to afford the silica-supported ruthenium complex 6.