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Search for "unsymmetrical N-heterocyclic carbenes" in Full Text gives 1 result(s) in Beilstein Journal of Organic Chemistry.
Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands
- Veronica Paradiso,
- Chiara Costabile and
- Fabia Grisi
Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292
- to the current state of research are discussed. Keywords: ligand design; olefin metathesis; ruthenium catalysts; selectivity; unsymmetrical N-heterocyclic carbenes; Introduction The transition metal-catalyzed olefin metathesis reaction is an indispensable synthetic tool for the construction of new
Graphical Abstract
Figure 1: Second-generation Grubbs (GII), Hoveyda (HGII), Grela (Gre-II), Blechert (Ble-II) and indenylidene-...
Figure 2: Grubbs (1a) and Hoveyda-type (1b) complexes with N-phenyl, N’-mesityl NHCs.
Figure 3: C–H insertion product 2.
Figure 4: Grubbs (3a–6a) and Hoveyda-type (3b–6b) complexes with N-fluorophenyl, N’-aryl NHCs.
Scheme 1: RCM of diethyl diallylmalonate (7).
Scheme 2: RCM of diethyl allylmethallylmalonate (9).
Scheme 3: RCM of diethyl dimethallylmalonate (11).
Scheme 4: CM of allylbenzene (13) with cis-1,4-diacetoxy-2-butene (14).
Scheme 5: ROMP of 1,5-cyclooctadiene (16).
Figure 5: Grubbs (18a–21a) and Hoveyda-type (18b–21b) catalysts bearing uNHCs with a hexafluoroisopropylalkox...
Figure 6: A Grubbs-type complex with an N-adamantyl, N’-mesityl NHC 22 and the Hoveyda-type complex with a ch...
Figure 7: Grubbs (24a and 25a) and Hoveyda-type (24b and 25b) complexes with N-alkyl, N’-mesityl NHCs.
Figure 8: Grubbs-type complexes 31–34 with N-alkyl, N’-mesityl NHCs.
Figure 9: Grubbs-type complex 35 with an N-cyclohexyl, N’-2,6-diisopropylphenyl NHC.
Figure 10: Hoveyda-type complexes with an N-alkyl, N’-mesityl (36, 37) and an N-alkyl, N’-2,6-diisopropylpheny...
Figure 11: Indenylidene-type complexes 41–43 with N-alkyl, N’-mesityl NHCs.
Figure 12: Grubbs-type complex 44 and its monopyridine derivative 45 containing a chiral uNHC.
Scheme 6: Alternating copolymerization of 46 with 47 and 48.
Figure 13: Pyridine-containing complexes 49–52 and Grubbs-type complex 53.
Figure 14: Hoveyda-type complexes 54–58 in the alternating ROMP of NBE (46) and COE (47).
Figure 15: Catalysts 59 and 60 in the tandem RO–RCM of 47.
Figure 16: Hoveyda-type complexes 61–69 with N-alkyl, N’-aryl NHCs.
Scheme 7: Ethenolysis of methyl oleate (70).
Scheme 8: AROCM of cis-5-norbornene-endo-2,3-dicarboxylic anhydride (75) with styrene.
Figure 17: Hoveyda-type catalysts 79–82 with N-tert-butyl, N’-aryl NHCs.
Scheme 9: Latent ROMP of 83 with catalyst 82.
Figure 18: Indenylidene and Hoveyda-type complexes 85–92 with N-cycloalkyl, N’-mesityl NHCs.
Scheme 10: RCM of N,N-dimethallyl-N-tosylamide (93) with catalyst 85.
Scheme 11: Self metathesis of 13 with catalyst 85.
Figure 19: Grubbs-type complexes 98–104 with N-alkyl, N’-mesityl NHCs.
Figure 20: Grubbs-type complexes 105–115 with N-alkyl, N’-mesityl ligands.
Figure 21: Complexes 116 and 117 bearing a carbohydrate-based NHC.
Figure 22: Complexes 118 and 119 bearing a hemilabile amino-tethered NHC.
Figure 23: Indenylidene-type complexes 120–126 with N-benzyl, N’-mesityl NHCs.
Scheme 12: Diastereoselective ring-rearrangement metathesis (dRRM) of cyclopentene 131.
Figure 24: Indenylidene-type complexes 134 and 135 with N-nitrobenzyl, N’-mesityl NHCs.
Figure 25: Hoveyda-type complexes 136–138 with N-benzyl, N’-mesityl NHCs.
Figure 26: Hoveyda-type complexes 139–142 with N-benzyl, N’-Dipp NHC.
Figure 27: Indenylidene (143–146) and Hoveyda-type (147) complexes with N-heteroarylmethyl, N’-mesityl NHCs.
Figure 28: Hoveyda-type complexes 148 and 149 with N-phenylpyrrole, N’-mesityl NHCs.
Figure 29: Grubbs-type complexes with N-trifluoromethyl benzimidazolidene NHCs 150–153, 155 and N-isopropyl be...
Scheme 13: Ethenolysis of ethyl oleate 156.
Scheme 14: Ethenolysis of cis-cyclooctene (47).
Figure 30: Grubbs-type C1-symmetric (164) and C2-symmetric (165) catalysts with a backbone-substituted NHC.
Figure 31: Possible syn and anti rotational isomers of catalyst 164.
Scheme 15: ARCM of substrates 166, 168 and 170.
Figure 32: Hoveyda (172) and Grubbs-type (173,174) backbone-substituted C1-symmetric NHC complexes.
Scheme 16: ARCM of 175,177 and 179 with catalyst 174.
Figure 33: Grubbs-type C1-symmetric NHC catalysts bearing N-propyl (181, 182) or N-benzyl (183, 184) groups on...
Scheme 17: ARCM of 185 and 187 promoted by 184 to form the encumbered alkenes 186 and 188.
Figure 34: N-Alkyl, N’-isopropylphenyl NHC ruthenium complexes with syn (189, 191) and anti (190, 192) phenyl ...
Figure 35: Hoveyda-type complexes 193–198 bearing N-alkyl, N’-aryl backbone-substituted NHC ligands.
Scheme 18: ARCM of 166 and 199 promoted by 192b.
Figure 36: Enantiopure catalysts 201a and 201b with syn phenyl units on the NHC backbone.
Figure 37: Backbone-monosubstituted catalysts 202–204.
Figure 38: Grubbs (205a) and Hoveyda-type (205b) backbone-monosubstituted catalysts.
Scheme 19: AROCM of 206 with allyltrimethylsilane promoted by catalyst 205a.
