In recent years, the olefin metathesis reaction has attracted widespread attention as a versatile carbon−carbon bond-forming method. Many new applications have become possible because of major advances in catalyst design. State-of-the-art ruthenium catalysts are not only highly active but also compatible with most functional groups and easy to use. This Account traces the ideas and discoveries that were instrumental in the development of these catalysts, with particular emphasis on (PCy3)2Cl2RuCHPh and its derivatives. The discussion includes an analysis of trends in catalyst activity, a description of catalysts coordinated with N-heterocyclic carbene ligands, and an overview of ongoing work to improve the activity, stability, and selectivity of this family of L2X2RuCHR complexes.

http://web4.uwindsor.ca/users/j/jlichaa/reference.nsf/0/10ff8b04ff3a317885256d88005720f6/$FILE/acr-2001-34-18-metath-grubbs.pdf

The Development of L2X2RuCHR Olefin Metathesis Catalysts: An Organometallic Success Story

Strong Closed-Shell Interactions in Inorganic Chemistry.

The reactions of RuCl2(PPh3)3 with a number of diazoalkanes were surveyed, and alkylidene transfer to give RuCl2(CHR)(PPh3)2 (R = Me (1), Et (2)) and RuCl2(CH-p-C6H4X)(PPh3)2 (X = H (3), NMe2 (4), OMe (5), Me (6), F (7), Cl (8), NO2 (9)) was observed for alkyl diazoalkanes RCHN2 and various para-substituted aryl diazoalkanes p-C6H4XCHN2. Kinetic studies on the living ring-opening metathesis polymerization (ROMP) of norbornene using complexes 3−9 as catalysts have shown that initiation is in all cases faster than propagation (ki/kp = 9 for 3) and that the electronic effect of X on the metathesis activity of 3−9 is relatively small. Phosphine exchange in 3−9 with tricyclohexylphosphine leads to RuCl2(CH-p-C6H4X)(PCy3)2 10−16, which are efficient catalysts for ROMP of cyclooctene (PDI = 1.51−1.63) and 1,5-cyclooctadiene (PDI = 1.56−1.67). The crystal structure of RuCl2(CH-p-C6H4Cl)(PCy3)2 (15) indicated a distorted square-pyramidal geometry, in which the two phosphines are trans to each other, and the alkyli...

Synthesis and Applications of RuCl2(CHR‘)(PR3)2: The Influence of the Alkylidene Moiety on Metathesis Activity

Ru-, Rh-, and Pd-Catalyzed C-C Bond Formation Involving C-H Activation and Addition on Unsaturated Substrates: Reactions and Mechanistic Aspects

The advent of well-defined catalysts for olefin metathesis which combine high activity, durability, and excellent tolerance towards polar functional groups has revolutionized the field. The past decade has seen the rapid embrace of these reagents as tools for advanced organic and polymer chemistry and the success of this development is witnessed by a plethora of elegant applications to the synthesis of natural and nonnatural products. This review article provides an overview of these developments and intends to familiarize the reader with some very recent advances which hold the promise to expand the scope of the reaction even further. Moreover, the positive impact of metathesis on the fundamental logic of retrosynthetic planning is demonstrated by means of typical examples. Finally, it will be shown that metathesis is by no means restricted to alkenes as substrates, and some comments on metathesis reactions following unconventional mechanistic pathways will also be presented.

Olefin Metathesis and Beyond

Basische metalle: LI. Neuartige hydridorhodium(III)- und -iridium(III)-komplexe mit triisopropylphosphan-liganden. Die dihydrido-verbindungen C5H5MH2(PR′3) als metall-basen☆

Five-Coordinate 16-Electron Carbene- and Vinylideneruthenium(II) Complexes Prepared from [RuCl2(C8H12)]n or from the New Dihydridoruthenium(IV) Compound [RuH2Cl2(PiPr3)2]

Justin Wolf

Papers

Basische metalle: LI. Neuartige hydridorhodium(III)- und -iridium(III)-komplexe mit triisopropylphosphan-liganden. Die dihydrido-verbindungen C5H5MH2(PR′3) als metall-basen☆

Five-Coordinate 16-Electron Carbene- and Vinylideneruthenium(II) Complexes Prepared from [RuCl2(C8H12)]n or from the New Dihydridoruthenium(IV) Compound [RuH2Cl2(PiPr3)2]

Metal‐Mediated Synthesis of 1,4‐Di‐tert‐butyl‐1,4‐azaborine

Synthesis of [C5H5Rh(PhCCH)P(iPr)3] and [C5H5Rh(CCHPh)P(iPr)3]: Mechanism of the Conversion of an Alkyne Ligand into a Vinylidene Ligand

Synthesis and Structure of trans‐[MCl(CCHR)(PiPr3)2] (MRh, Ir): The First Square‐Planar Vinylidenemetal Complexes