Olefin metathesis, or alkene metathesis, is an important process in petroleum refining and in the synthesis of important compounds such as pharmaceuticals.
The mechanism of olefin metathesis is related to pericyclic reactions like Diels Alder and [2 2] reactions.
In larger scale, industrial reactions, air- and moisture-sensitivity is usually a less compelling factor than speed. D., College of Saint Benedict / Saint John's University (with contributions from other authors as noted).
In addition to the simple "partner-swapping" of olefin metathesis, which is very important to the petroelum industry, there are other useful variations on the reaction.
In particular, terminal olefins (with the double bond at the end of the chain) are converted into internal olefins (with the double bond somewhere in the middle of the chain). The surface of the metal oxides may be covered with a mixture of hydroxyl groups as well as terminal oxides (M=O groups).
The terminal oxides on the surface are the important part of the catalyst.
A variety of catalysts have been developed for olefin metathesis.
The laboratories of Bob Grubbs at Cal Tech and Dick Schrock at MIT have been particularly important in this area, although other labs have contributed significantly, including that of Amir Hoveyda at Boston College.
The reaction, it turns out, involves a [2 2] cycloaddition of an alkene to a metal alkylidene (to the metal-carbon double bond).
This reaction results in a four-membered ring, called a metallacyclobutane.