Amine-Mediated Degradation in Olefin Metathesis Reactions that Employ the Second-Generation Grubbs Catalyst

作者：Lummiss Justin A M; Ireland Benjamin J; Sommers Jacob M; Fogg Deryn E^*

来源：ChemCatChem, 2014, 6(2): 459-463.

DOI：10.1002/cctc.201300861

• amines
• homogeneous catalysis
• deactivation
• nucleophile
• olefin metathesis

Amine-mediated decomposition during olefin metathesis reactions that employ the second-generation Grubbs catalyst is studied. For most amines, the dominant deactivation pathway involves ejection of the PCy3 (Cy=cyclohexyl) ligand by the amine, followed by abstraction of the methylidene moiety from the resting-state species RuCl2(H(2)IMes)(PCy3)(=CH2) (H(2)IMes=1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) as [MeP-Cy-3]Cl. An exception is highly basic 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), which is slow to degrade the resting-state methylidene complex, and for which the phosphonium byproduct is not observed. However, DBU is shown to rapidly attack a species generated during catalysis, most probably the metallacyclobutane intermediate.

• 出版日期2014-2