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Amine‐Mediated Degradation in Olefin Metathesis Reactions that Employ the Second‐Generation Grubbs Catalyst
Author(s) -
Lummiss Justin A. M.,
Ireland Benjamin J.,
Sommers Jacob M.,
Fogg Deryn E.
Publication year - 2014
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201300861
Subject(s) - chemistry , imes , catalysis , metathesis , allene , moiety , medicinal chemistry , grubbs' catalyst , amine gas treating , salt metathesis reaction , ligand (biochemistry) , carbene , olefin fiber , organic chemistry , combinatorial chemistry , polymerization , biochemistry , polymer , receptor
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 PCy 3 (Cy=cyclohexyl) ligand by the amine, followed by abstraction of the methylidene moiety from the resting‐state species RuCl 2 (H 2 IMes)(PCy 3 )(=CH 2 ) (H 2 IMes=1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene) as [MePCy 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.