The influence of the structure of cationic molybdenum imido alkylidene N-heterocyclic carbene
(NHC) catalysts, i. e. of [Mo(N-2-tert-butyl-C6H4) (CHCMe2Ph)(NHC)X+ B(ArF)4
] (NHC=1,3-di(2-Pr)
imidazol-2-ylidene (iPr), 1,3-dimesitylimidazol-2-ylidene (IMes); X=pyrrolide, OCH(CF3)2, B(ArF)4
=
tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) and of [Mo(N-3,5-Me2-C6H3)(CHCMe2Ph)(NHC)(CH3CN)X+
B(ArF)4
] (NHC=1,3-dimesitylimidazol-2-ylidene, 1,3-dimesitylimidazolin-2-ylidene (IMesH2); X=CF3SO3,
OCPh(CF3)2) on E/Z-selectivity in the ring-opening cross-metathesis (ROCM) of endo, endo-2,3-
dicarbomethoxynorborn-5-ene (endo, endo-DCMNBE), exo, exo-2,3-dicarbomethoxynorborn-5-ene (exo, exo-
DCMNBE), endo, exo-2,3-dicarbomethoxynorborn-5-ene ((+) DCMNBE) and 2,3-exo,exo-bis(acetoxymethyl)-
7-oxabicyclo[2.2.l]hept-5-ene (7-oxa-NBE) with 1-pentene, styrene, allyltrimethylsilane, allyl benzyl ether,
allyl phenyl ether and allyl ethyl ether has been studied. With the exception of the ROCM reaction of endo,
endo-DCMNBE with styrene, all other ROCM reactions of endo, endo-DCMNBE proceeded under
thermodynamic control without any post-metathesis isomerization reactions with full retention of the
configuration of the newly formed 1,2-disubstituted double bond as confirmed by kinetic studies. Similar
accounts for selected homometathesis reactions. Catalyst structure-selectivity correlations based on the buried
volume, Vbur, of the N-imido ligand are presented.
All primary data files and processed data of the journal article from Buchmeiser group.
