Edwin van der Eide

Alkene metathesis is a powerful C=C bond breaking and making transformation which has been applied to the synthesis of polymers, pharmaceuticals, natural products and other organic molecules.¹ Metathesis catalysts based on ruthenium are very popular due to their high functional group tolerance and their stability under ambient conditions. Although well-defined ruthenium alkylidene catalysts started to be developed in 1992,² the ruthenacyclobutanes that were thought to be involved in the catalysis were never detected. The discovery of phosphine-free, fast-initiating ruthenium phosphonium alkylidenes in our group changed this, and a ruthenacyclobutane relevant to alkene metathesis was finally disclosed in 2005.³ This lecture presents the results of ongoing fundamental research in our lab on ruthenium phosphonium alkylidenes. A mechanistic study on the intermediates involved in the ruthenium-catalyzed ring-closing metathesis of dimethyl diallylmalonate is presented.

(1) Handbook of Metathesis; Grubbs, R. H., Ed.; Wiley-VCH: Weinheim, 2003; Vol. 1-3.

(2) Nguyen, S. T.; Johnson, L. K.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1992, 114, 3974.

(3) Romero, P. E.; Piers, W. E. J. Am. Chem. Soc. 2005, 127, 5032.