Does the rate of competing isomerisation during alkene metathesis depend on pre-catalyst initiation rate?
Experimental studies of the ring-closing metathesis reaction of 1,8-nonadiene and the ROMP reaction of cycloheptene show that the rate of isomerisation is not correlated to the initiation rate of the pre-catalyst, and that the absence of phosphine leads to a greatly increased rate of isomerisation. A range of pre-catalysts and solvents were probed and it is proposed that the isomerisation is mediated by a ruthenium hydride complex; our results are consistent with the rate-determining formation of such a species, which might be trapped in situ by tricyclohexylphosphane.
WestCHEM/Department of Pure & Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK. david.nelson@strath.ac.uk jonathan.percy@strath.ac.uk.
David J
DJ
Nelson
Jonathan M
JM
Percy
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D007536:Isomerism; D010720:Phosphines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
D000475:Alkenes; D010720:Phosphines; D012428:Ruthenium; C044646:phosphine