Olefin Metathesis Catalyst

Recently, olefin metathesis reaction employing metallic carbene complex as a catalyst is attracting a high degree of attention. Metathesis is referred to as a reaction in which an exchange of alkylidene group occurs between two olefin molecules.

In 1995 R.H. Grubbs and co-workers have developed the present reagent 1, as a metathesis catalyst. The catalyst 1 is characterized by being stable toward the oxygen and moisture in the atmosphere and inert to the presence of a variety of functional groups when compared with the conventional metathesis catalysts. The reactions using the catalyst 1 are mainly classified into ring-closing metathesis reaction and ring-opening cross metathesis reaction.

A great number of synthesis examples employing the catalyst 1 for metathesis reactions, have been reported²⁾ and its application toward synthesizing physiologically active substances have been increasingly carried out. For example, T. Oishi and co-workers have applied the catalyst 1 to the synthesis of polycyclic ethers³⁾ and K. C. Nicolau and co-workers utilized the catalyst 1 in the synthesis of epothilones A and B⁴⁾.