Olefin isomerization promoted by olefin metathesis catalysts

A model study was conducted to determine the extent to which olefin isomerization occurs during olefin metathesis of simple olefins with Grubbs ruthenium catalysts and Schrock's molybdenum catalyst under conditions similar to those employed in ADMET polymerization. It was found that the N-heterocyclic carbene (NHC)-ligated ruthenium complex promotes extensive isomerization of both internal and terminal olefins at temperatures of 50-60 degreesC, whereas the bisphosphine ruthenium complex and Schrock's molybdenum complex do not. Isomerization occurs concurrently with metathesis for the NHC ruthenium complex to produce a mixture of linear olefins of consecutive carbon numbers. (C) 2002 Elsevier Science B.V. All rights reserved.