Highly Active Silica Gel-Supported Metathesis (Pre)Catalysts

Abstract

Highly active Hoveyda-Grubbs and Hoveyda-Blechert type (pre)catalysts, immobilized on silica gel, are presented. These (pre)catalysts are synthesized in a few steps from readily available precursors and demonstrate high activity in a number of test metathesis reactions. The catalyst is easily separated by simple filtration of the non-swelling material.

Strategies to Immobilize Well‐Defined Olefin Metathesis Catalysts: Supported Homogeneous Catalysis vs. Surface Organometallic Chemistry

“…The main approach has been to anchor the benzylidene by a substituent of the phenyl ring attached to (Scheme 12): 1) a polyethyleneglycol (PEG) (12a), [69,70] 2) a dendrimer (12b), [71] 3) a polystyrene support via a butyldiethylsilyl linker (12c), [72] 4) silica via several types of organic linkers by Hoveyda (12d) [73,74] , Blechert (12e) [75] and Moreau (12f), [76] 5) silica with polymer linkers (12g), [77] 6) polymers based on polynorbornene (12h) [78] or copolymer of acrylate perfluoroester and acryloyl chloride (12i), [79] 7) a Wang resin (12j) [80] 8) via ionic interaction with a polymer (12k). [81] The other approach has been to anchor the benzylidene by the alkyl substituent of the ether group either to PS [82] or to PEG (Scheme 13).…”

Poly(norbornene)‐Supported N‐Heterocyclic Carbenes as Ligands in Catalysis

“…[89] To study the activity of these supported catalysts, the RCM of diethyl diallylmalonate in dichloromethane at 45 8C was investigated. [45,90,91] Under these reaction conditions, diethyl diallylmalonate was converted in 95 % yield to its corresponding RCM product, cyclopent-3-ene-1,1-dicarboxylic acid diethyl ester, within 20 min using 5.0 mol % of 9 (Table 1, Entry 15). This activity is comparable to other supported Grubbs catalyst analogues of 10 that convert diethyl diallylmalonate using similar catalyst loadings with the same conversions in the same time frame, [45,90,91] demonstrating that our supported catalyst is an active olefin metathesis catalyst.…”

Synthesis of Polypentenamer and Poly(Vinyl Alcohol) with a Phase‐Separable Polyisobutylene‐Supported Second‐Generation Hoveyda–Grubbs Catalyst

“…Some of the most commonly employed strategies to obtain supported metathesis catalysts consist of immobilizing the ruthenium alkylidene complex on to insoluble polymers, [19][20][21][22] soluble polymers, [23][24][25][26] inorganic supports, [27][28][29] perfluorinated, [30,31] and ionic-liquid tags [32][33][34][35] (Figure1).…”