Evaluation of Several Molybdenum and Ruthenium Catalysts for the Metathesis Homocoupling of 3-Methyl-1-Butene

Abstract

We synthesized Mo(NC[subscript 6]F[subscript 5])(CHCMe[subscript 2]Ph)(TPPO)(PPhMe[subscript 2])Cl (TPPO = 2,3,5,6‐tetraphenylphenoxide), Mo(NC[subscript 6]F[subscript 5])(CHCMe[subscript 2]Ph)(TTBTO)(PPhMe[subscript 2])Cl (TTBTO = 2,6‐di(3′,5′‐di‐tert‐butylphenyl)phenoxide), and Mo(NC[subscript 6]F[subscript 5])(CHCMe[subscript 2]Ph)(TPPO)(PPhMe[subscript 2])(CF[subscript 3]Pyr) (CF[subscript 3]Pyr = 3,4‐bistrifluoromethylpyrrolide), in order to evaluate them as catalysts for the homocoupling of 3‐methyl‐1‐butene. They were compared with Mo(NC[subscript 6]F[subscript 5])(CHCMe[subscript 2]Ph)(HMTO)(PPhMe[subscript 2])Cl (HMTO = 2,6‐dimesitylphenoxide), Mo(NC[subscript 6]F[subscript 5])(CHCMe[subscript 2]Ph)(HIPTO)(PPhMe[subscript 2])Cl (HIPTO = 2,6‐di(2′,4′,6′‐triisopropylphenyl)phenoxide), and several other Mo and Ru catalysts. In the best cases turnover numbers (TONs) of 400 – 700 were observed for the homocoupling of 3‐methyl‐1‐butene in a closed vessel (ethylene not removed). Keywords: Olefin metathesis, Homocoupling, Molybdenum, Ruthenium, 3‐Methyl‐1‐butene