Olefin metathesis catalyzed by zero-valent, anionic group VI metal compounds

Abstract

Complexes of the general type R 4N + [M(CO) 5X]− (where R is an alkyl radical, M a group VI metal and X a halide or carboxylate group) are very active and selective catalysts for the olefin metathesis reaction. These catalysts require an alkylaluminum compound activator. Alkylaluminum dihalides are especially effective and in general an A1:M ratio of greater than 1.5:1 is necessary. Of the group VI metals it was found that the molybdenum compounds produce the most active catalysts while of all the halide and carboxylate groups tested, chloride is the most effective. Surprisingly, only certain cations, such as ( n-C 4H 9) 4N +, give active catalysts. The effectiveness of these catalysts for the conversion of a number of pure olefins and olefin mixtures was tested. Some information regarding the composition of the actual active catalysts has been obtained.