The chemistry of the carbon–transition metal double and triple bond: annual survey covering the year 1998

Abstract

This survey is intended to be a comprehensive summary of articles, which report on the synthesis, reactivity, or properties of compounds that feature a multiple bond between carbon and a transition metal. Reactions that employ metal carbene complexes as transient intermediates generated through well-established routes [this subject was reviewed in 1998: M.P. Doyle, M.N. Protopopova, Tetrahedron 54 (1998) 7919] are not covered unless there is some effort to characterize the carbene complex intermediate. Although a determined effort has been made to include patents, in general only patents that focus on carbene complexes and not polymer products will be included. Only compounds which feature a multiple bond between one carbon atom and one transition metal are discussed in this survey, thus bridging carbene and carbyne complexes are not covered unless there is a multiple bond to at least one transition metal. The complexes of stable carbenes with transition metals have not been included; since the π-donation component of these complexes is minimal, there is no formal carbon–metal multiple bond [see J.C. Green, R.G. Scurr, P.R. Arnold, F.G.N. Cloke, J. Chem. Soc. Chem. Commun. (1997) 1963, and A.A. Danopoulos, D.M. Hankin, G. Wilkinson, S.M. Cafferkey, T.K.N. Sweet, M.B. Hursthouse, Polyhedron 16 (1997) 3879]. This survey has been divided into two sections, metal carbene (or alkylidene) complexes and metal carbyne (or alkylidyne) complexes; the carbene complex section represents the vast majority of this article. The metal carbene section has been organized according to metal, starting from the left side of the periodic table. A special section focusing on alkene metathesis has been included prior to the discussion of carbene complexes of individual metals. The metal carbyne section has been organized according to reaction type.