Other Catalytic Reactions Promoted by Indenylidenes

Another application of ruthenium indenylidene complexes was the atom transfer radical addition of carbon tetrachloride to vinyl monomers reported by Verpoort [61]. This Kharasch reaction afforded good yields for all substrates tested, especially with the catalyst VIII (Equation 8.11, Table 8.8). 

The nature of the chlorinated reagent is crucial for promoting the Kharasch addition reaction (Equation 8.11). The results showed that carbon tetrachloride could be added to various olefins in a regioselective way. Under these reaction conditions, no polymerization products were detected. In contrast, when chloroform was used as the halide source the methyl methacrylate and styrene conversions reached only 33% and 40% with the best performing system (VIII), and a significant fraction of polymers was observed [61]. 

The indenylidene complexes IX and XXVIIIc were also reported to promote the addition of different carboxylic acids to terminal alkynes to give enol esters, the Markovnikov addition product being the major product with, in some cases, the competing catalytic dimerization of terminal alkynes [61]. 

Chauvin, Y. (1973) Comptes Rmdus de L Academic des Sciences, Paris, 276, 169. Chauvin, Y, Commereuc, D. and Cmypehnck, D. (1976) Makromolekulare Chemie, 177, 2637. 

3 Schrock, R.R., Murdzek, J.S., Bazan, G.C., Robbins, J., Di Mare, M. and O Regan, M. (1990) Journal (fdieAmerican Chemical Society, 112, 3875 Schrock, R.R. (2004) Journal of Molecular Catalysis AChemical, 213,21. 

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