Metathesis history

Manufacture. The history of ammonium chloride manufacture is linked to the birth of the soda and synthetic ammonia iadustries. Consequendy this haUde has always been a by-product ia great supply. Production by direct reaction of ammonia and hydrochloric acid is simple but usually economically unattractive a process based on metathesis or double decomposition is generally preferred. 

A closer look on the history of the development of catalyst 52 shows that this class of compounds was to some degree predestined for the application of NHCs. Complex 51 containing triphenylphosphines is an active catalyst for olefin metathesis. However, the substitution of the triphenylphosphines by more electron-donating and sterically more demanding tricyclohexylphosphines is accompanied by a significantly increased stability and catalytic performance " Thus, complexes of type 53 58,2S5 logical development with respect... 

Although silver chemistry has a long history in organic chemistry, it has typically been used in stoichiometric amounts and is developed mostly for anion metathesis... 

Olefin metathesis has quickly become one of the most widely used methods for mild carbon-carbon bond formation in organic synthesis [1,2]. With the development of highly active, fimctional group-tolerant catalysts, like Grubbs second generation catalyst ([Ru] ), metathesis has been successfully applied across many areas of research, and some reviews already exist that deal with metathesis catalysis and applications [1-5]. This review focuses on recent developments in acycUc diene metathesis (ADMET) polymerization chemistry and methodology that have been published over the past five years, starting with a short discussion on the history of olefin metathesis and ADMET polymerization. 

This chapter will present some of the history of ADMET and olefin metathesis in general, although the emphasis will be on the mechanism and kinetics of ADMET polymerization. The general mechanism for olefin metathesis will be presented before any of the specific catalyst structures are introduced or discussed in order to provide the reader with a firm basis upon which to compare the various popularly used catalysts for ADMET polymerization. In addition, procedural information will be given at the end of the chapter to give the reader an idea of what is specifically involved in a typical ADMET polymerization. 

Rouhi, A. Maureen. Olefin Metathesis Big-Deal Reaction. Chemical Engineering News 80 (December 23, 2002) 29-33 Olefin Metathesis The Early Days. Chemical Engineering News 80 (December 23, 2002) 34—38. These two brief articles explain the complex history of the discovery of the olefin metathesis reaction as well as its applications. 

Having traversed some of the key events in the history of olefin metathesis, it is now appropriate to discuss some of the resultant fruits of that early labor in the form of practical applications in organic synthesis. Since the general reaction was bom in the industrial sector, we felt it appropriate to commence with some examples of commercial processes. Among several of the profitable industrial procedures that benefit from olefin metathesis, one of the oldest is the Phillips triolefin process (Scheme 7a) which utilizes a molybdenum-based catalyst system to convert propene (17) into a mixture of 2-butene (18) and ethene (19). These products are then used as monomers for polymer synthesis as well as for general use in petroleum-related applications. The reverse reaction can also be employed to prepare propene for alternative uses. 

During the past two decades, the alkene metathesis reaction has developed from its early appUcations in large-scale processes with heterogeneous and ill-defined catalyst systems to a standard technique in synthetic chemistry and polymer laboratories. The development of well-defined and often bench-stable precatalysts " has been key to the widespread use of alkene metathesis in modem target synthesis projects. The impact of this useful reaction was recognized in 2005 by the award of the Nobel Prize in Chemistry to Yves Chauvin, Robert Gmbbs, and Richard Schrock. Astmc has published an excellent article on the early history of the alkene metathesis reaction, which covers the determination of the mechanism and the rejection of alternative hypotheses, so this early history will not be discussed here. 

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