2nd Generation Piers Catalyst1
(PCy3 = tricyclohexylphosphine)
– CAS#: [832146-68-6]
– FW: 858.67
– Color: Brown
– Initiation temperature: <0 °C
|CM||-Synthesis of 1,2-disubstituted olefins from terminal olefins||-Slower than 2nd Generation Grubbs Catalyst for CM of internal olefins|
|RCM||-Synthesis of 1,2-disubstituted and trisubstituted olefins
-Reacts at low temperatures
-Decomposes more readily than 2nd Generation Grubbs Catalyst at elevated temperatures
This catalyst is commonly known as the 2nd Generation Piers Catalyst. This is the N-heterocyclic carbene version of Piers’ fast-initiating 4-coordinate catalysts. It’s fast to initiate because it doesn’t require any ligand dissociation to become activated. In the presence of olefin, the catalyst will begin to turn over as low as -50 °C. It’s because of this that Romero and Piers were able to use it to directly observe a metallocyclobutane intermediate by low temperature NMR.2
1 Romero, P. E.; Piers, W. E.; McDonald, R. Angew. Chem. Int. Ed. 2004, 43, 6161.
2 Romero, P. E.; Piers, W. E. J. Am. Chem. Soc. 2005, 127, 5032.
CM – Cross Metathesis
RCM – Ring Closing Metathesis