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DOI: 10.1055/s-2006-934413
Ring-Closure Metathesis Using a Covalently Immobilized Grubbs Catalyst
F. Michalek, D. Mädge, J. Rühe, W. Bannwarth*
Albert-Ludwigs-Universität, Freiburg, Germany
Publication History
Publication Date:
21 April 2006 (online)
Significance
The synthesis and application of novel solid-phase-bound Hoveyda-type catalysts and their successful application in RCM reactions in scCO2 were described. Thus, the immobilized catalyst 4 was prepared in three steps starting from Hoveyda-type ligand 2 anchored on a novel hybrid silica gel. The reaction of carboxylic acid 2 with a new support material 1 gave the desired compound 3. Acylation of 3 to mask the unreacted amino residue followed by complexation with 5 in the presence of CuCl gave the solid-bound catalyst 4. The RCM reaction of N,N-diallyltosylamine was carried out in the presence of 5 in scCO2 to give 2,5-dihydropyrrole in 93% yield. This catalyst was recovered and reused twice without significant loss of catalytic activity.