Search for "NHC ligand" in Full Text gives 65 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51
Graphical Abstract
Scheme 1: Representative transition-metal catalysis for allylic substitution.
Scheme 2: Formation of stereogenic centers in copper-catalyzed allylic alkylation reactions.
Scheme 3: Copper-mediated, stereospecific SN2-selective allylic substitution through retentive transmetalatio...
Scheme 4: ZnCl2-promoted stereospecific SN2' allylic substitution of secondary alkylcopper species via sequen...
Scheme 5: Temperature and time-dependent configurational stability of chiral secondary organocopper species.
Scheme 6: DFT analysis of B–C bond lengths in various boronate complexes and correlation with reactivity.
Scheme 7: Copper-catalyzed stereospecific allylic alkylation of secondary alkylboronic esters via tert-butyll...
Scheme 8: Copper-catalyzed stereospecific allylic alkylation of chiral tertiary alkylboronic esters via adama...
Scheme 9: DFT-calculated energy surface for boron-to-copper transmetalation of either the tert-butyl group or...
Scheme 10: CuH-catalyzed enantioselective allylic substitution and postulated catalytic cycle.
Scheme 11: CuH-catalyzed enantioselective allylic substitution of vinylarenes.
Scheme 12: CuH-catalyzed stereoselective allylic substitution of vinylboronic esters.
Scheme 13: (a) Generation of chiral copper species via enantioselective CuH addition to vinylBpin. (b) Regardi...
Scheme 14: CuH-catalyzed enantioselective allylic substitution of 1‐trifluoromethylalkenes with 18-crown-6.
Scheme 15: CuH-catalyzed enantioselective allylic substitution of terminal alkynes.
Scheme 16: Copper-catalyzed enantiotopic-group-selective allylic substitution of 1,1-diborylalkanes.
Scheme 17: (a) Computational and (b) experimental studies to elucidate the mechanistic details of the enantiot...
Scheme 18: Copper-catalyzed regio-, diastereo- and enantioselective allylic substitution of 1,1-diborylalkanes....
Scheme 19: (a) Experimental and (b) computational studies to understand the stereoselectivities in oxidative a...
Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273
Graphical Abstract
Figure 1: Examples of important azafluoranthene and benzo[j]fluoranthene natural products, and acenaphthylene...
Scheme 1: Selected synthetic strategies towards heterocyclic fluoranthene analogues, and our approach.
Scheme 2: Synthesis of benzo[j]fluoranthene 18.
Scheme 3: Synthesis of benzo[j]fluoranthene 23.
Scheme 4: Synthesis of benzo[j]fluoranthene 28.
Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227
Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54
Graphical Abstract
Figure 1: Laterally fused NHC motifs.
Scheme 1: Synthetic studies into the formation of a 3-aminoimdazo[5,1-b]oxazol-6-ium motif based on a gold-ca...
Scheme 2: The synthesis of AImOxAu(I)Cl, AImOxCu(I)Cl, and AImOxIr(CO)2Cl complexes from 6a. The single cryst...
Scheme 3: Use of AImOxAuCl 13 in catalysis. aYields are calculated from the 1H NMR spectra against an interna...
Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102
Graphical Abstract
Scheme 1: In situ generation of imidazolylidene carbene.
Scheme 2: Hg(II) complex of NHC.
Scheme 3: Isolable and bottlable carbene reported by Arduengo [3].
Scheme 4: First air-stable carbene synthesized by Arduengo in 1992 [5].
Figure 1: General structure of an NHC.
Figure 2: Stabilization of an NHC by donation of the lone pair electrons into the vacant p-orbital (LUMO) at ...
Figure 3: Abnormal NHC reported by Bertrand [8,9].
Figure 4: Cu(d) orbital to σ*C-N(NHC) interactions in NHC–CuX complexes computed at the B3LYP/def2-SVP level ...
Figure 5: Molecular orbital contributions to the NHC–metal bond.
Scheme 5: Synthesis of NHC–Cu(I) complexes by deprotonation of NHC precursors with a base.
Scheme 6: Synthesis of [NHC–CuX] complexes.
Scheme 7: Synthesis of [(ICy)CuX] and [(It-Bu)CuX] complexes.
Scheme 8: Synthesis of iodido-bridged copper–NHC complexes by deprotonation of benzimidazolium salts reported...
Scheme 9: Synthesis of copper complexes by deprotonation of triazolium salts.
Scheme 10: Synthesis of thiazolylidene–Cu(I) complex by deprotonation with KOt-Bu.
Scheme 11: Preparation of NHC–Cu(I) complexes.
Scheme 12: Synthesis of methylmalonic acid-derived anionic [(26a,b)CuCl]Li(THF)2 and zwitterionic (28) heterol...
Scheme 13: Synthesis of diaminocarbene and diamidocarbene (DAC)–Cu(I) complexes.
Scheme 14: Synthesis of the cationic (NHC)2Cu(I) complex 39 from benzimidazolium salts 38 with tetrakis(aceton...
Scheme 15: Synthesis of NHC and ADC (acyclic diamino carbenes) Cu(I) hexamethyldisilazide complexes reported b...
Scheme 16: Synthesis of NHC–copper(I) complexes using an acetylacetonate-functionalized imidazolium zwitterion...
Scheme 17: Synthesis of NHC–Cu(I) complexes through deprotonation of azolium salts with Cu2O.
Scheme 18: Synthesis of NHC–CuBr complex through deprotonation with Cu2O reported by Kolychev [31].
Scheme 19: Synthesis of chiral NHC–CuBr complexes from phenoxyimine-imidazolium salts reported by Douthwaite a...
Scheme 20: Preparation of linear neutral NHC–CuCl complexes through the use of Cu2O. For abbreviations, please...
Scheme 21: Synthesis of abnormal-NHC–copper(I) complexes by Bertrand, Cazin and co-workers [35].
Scheme 22: Microwave-assisted synthesis of thiazolylidene/benzothiazolylidene–CuBr complexes by Bansal and co-...
Scheme 23: Synthesis of NHC–CuX complexes through transmetallation.
Scheme 24: Preparation of six- or seven-membered NHC–Cu(I) complexes through transmetalation from Ag(I) comple...
Scheme 25: Synthesis of 1,2,3-triazolylidene–CuCl complexes through transmetallation of Ag(I) complexes genera...
Scheme 26: Synthesis of NHC–copper complexes having both Cu(I) and Cu(II) units through transmetalation report...
Scheme 27: Synthesis of new [(IPr(CH2)3Si(OiPr)3)CuX] complexes and anchoring on MCM-41.
Scheme 28: Synthesis of bis(trimethylsilyl)phosphide–Cu(I)–NHC complexes through ligand displacement.
Scheme 29: Synthesis of silyl- and stannyl [(NHC)Cu−ER3] complexes.
Scheme 30: Synthesis of amido-, phenolato-, thiophenolato–Cu(NHC) complexes.
Scheme 31: Synthesis of first isolable NHC–Cu–difluoromethyl complexes reported by Sanford et al. [44].
Scheme 32: Synthesis of NHC–Cu(I)–bifluoride complexes reported by Riant, Leyssens and co-workers [45].
Scheme 33: Conjugate addition of Et2Zn to enones catalyzed by an NHC–Cu(I) complex reported by Woodward in 200...
Scheme 34: Hydrosilylation of a carbonyl group.
Scheme 35: NHC–Cu(I)-catalyzed hydrosilylation of ketones reported by Nolan et al. [48,49].
Scheme 36: Application of chiral NHC–CuCl complex 104 for the enantioselective hydrosilylation of ketones.
Scheme 37: Hydrosilylation reactions catalyzed by NHC–Cu(Ot-Bu) complexes.
Scheme 38: NHC–CuCl catalyzed carbonylative silylation of alkyl halides.
Scheme 39: Nucleophilic conjugate addition to an activated C=C bond.
Figure 6: Molecular electrostatic potential maps (MESP) of two NHC–CuX complexes computed at the B3LYP/def2-S...
Scheme 40: Conjugate addition of Grignard reagents to 3-alkyl-substituted cyclohexenones catalyzed by a chiral...
Scheme 41: NHC–copper complex-catalyzed conjugate addition of Grignard reagent to 3-substituted hexenone repor...
Scheme 42: Conjugate addition or organoaluminum reagents to β-substituted cyclic enones.
Scheme 43: Conjugate addition of boronates to acyclic α,β-unsaturated carboxylic esters, ketones, and thioeste...
Scheme 44: NHC–Cu(I)-catalyzed hydroboration of an allene reported by Hoveyda [63].
Scheme 45: Conjugate addition of Et2Zn to cyclohexenone catalyzed by NHC–Cu(I) complex derived from benzimidaz...
Scheme 46: Asymmetric conjugate addition of diethylzinc to 3-nonen-2-one catalyzed by NHC–Cu complexes derived...
Scheme 47: General scheme of a [3 + 2] cycloaddition reaction.
Scheme 48: [3 + 2] Cycloaddition of azides with alkynes catalyzed by NHC–Cu(I) complexes reported by Diez-Gonz...
Scheme 49: Application of NHC–CuCl/N-donor combination to catalyze the [3 + 2] cycloaddition of benzyl azide w...
Scheme 50: [3 + 2] Cycloaddition of azides with acetylenes catalyzed by bis(NHC)–Cu complex 131 and mixed NHC–...
Figure 7: NHC–CuCl complex 133 as catalyst for the [3 + 2] cycloaddition of alkynes with azides at room tempe...
Scheme 51: [3 + 2] Cycloaddition of a bulky azide with an alkynylpyridine using [(NHC)Cu(μ-I)2Cu(NHC)] copper ...
Scheme 52: [3 + 2] Cycloaddition of benzyl azide with phenylacetylene under homogeneous and heterogeneous cata...
Scheme 53: [3 + 2] Cycloaddition of benzyl azide with acetylenes catalyzed by bisthiazolylidene dicopper(I) co...
Figure 8: Copper (I)–NHC linear coordination polymer 137 and its conversion into tetranuclear (138) and dinuc...
Scheme 54: An A3 reaction.
Scheme 55: Synthesis of SiO2-immobilized NHC–Cu(I) catalyst 141 and its application in the A3-coupling reactio...
Scheme 56: Preparation of dual-purpose Ru@SiO2–[(NHC)CuCl] catalyst system 142 developed by Bordet, Leitner an...
Scheme 57: Application of the catalyst system Ru@SiO2–[Cu(NHC)] 142 to the one-pot tandem A3 reaction and hydr...
Scheme 58: A3 reaction of phenylacetylene with secondary amines and aldehydes catalyzed by benzothiazolylidene...
Figure 9: Kohn–Sham HOMOs of phenylacetylene and NHC–Cu(I)–phenylacetylene complex computed at the B3LYP/def2...
Figure 10: Energies of the FMOs of phenylacetylene, iminium ion, and NHC–Cu(I)–phenylacetylene complex compute...
Scheme 59: NHC–Cu(I) catalyzed diboration of ketones 147 by reacting with bis(pinacolato)diboron (148) reporte...
Scheme 60: Protoboration of terminal allenes catalyzed by NHC–Cu(I) complexes reported by Hoveyda and co-worke...
Scheme 61: NHC–CuCl-catalyzed borylation of α-alkoxyallenes to give 2-boryl-1,3-butadienes.
Scheme 62: Regioselective hydroborylation of propargylic alcohols and ethers catalyzed by NHC–CuCl complexes 1...
Scheme 63: NHC–CuOt-Bu-catalyzed semihydrogenation and hydroborylation of alkynes.
Scheme 64: Enantioselective NHC–Cu(I)-catalyzed hydroborations of 1,1-disubstituted aryl olefins reported by H...
Scheme 65: Enantioselective NHC–Cu(I)-catalyzed hydroboration of exocyclic 1,1-disubstituted alkenes reported ...
Scheme 66: Markovnikov-selective NHC–CuOH-catalyzed hydroboration of alkenes and alkynes reported by Jones et ...
Scheme 67: Dehydrogenative borylation and silylation of styrenes catalyzed by NHC–CuOt-Bu complexes developed ...
Scheme 68: N–H/C(sp2)–H carboxylation catalyzed by NHC–CuOH complexes.
Scheme 69: C–H Carboxylation of benzoxazole and benzothiazole derivatives with CO2 using a 1,2,3-triazol-5-yli...
Scheme 70: Use of Cu(I) complex derived from diethylene glycol-functionalized imidazo[1,5,a] pyridin-3-ylidene...
Scheme 71: Allylation and alkenylation of polyfluoroarenes and heteroarenes catalyzed by NHC–Cu(I) complexes r...
Scheme 72: Enantioselective C(sp2)–H allylation of (benz)oxazoles and benzothiazoles with γ,γ-disubstituted pr...
Scheme 73: C(sp2)–H arylation of arenes catalyzed by dual NHC–Cu/NHC–Pd catalytic system.
Scheme 74: C(sp2)–H Amidation of (hetero)arenes with N-chlorocarbamates/N-chloro-N-sodiocarbamates catalyzed b...
Scheme 75: NHC–CuI catalyzed thiolation of benzothiazoles and benzoxazoles.
Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65
Graphical Abstract
Scheme 1: Concept of this work.
Scheme 2: Initial experiments for the trapping of the intermediate enolate Enl-1a with tropylium NTf2.
Scheme 3: The reaction scope.
Figure 1: Comparison of DFT-calculated and experimental ECD of (2R,3R)-4 and (2S,3R)-4.
Figure 2: DFT calculated (ωB97X-D4/def2-TZVPPD//PBEh-3c/def2-mSVP) HOMO energies and NBO charges for represen...
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90
Graphical Abstract
Figure 1: Representative shares of the global F&F market (2018) segmented on their applications [1].
Figure 2: General structure of an international fragrance company [2].
Figure 3: The Michael Edwards fragrance wheel.
Figure 4: Examples of oriental (1–3), woody (4–7), fresh (8–10), and floral (11 and 12) notes.
Figure 5: A basic depiction of batch vs flow.
Scheme 1: Examples of reactions for which flow processing outperforms batch.
Scheme 2: Some industrially important aldol-based transformations.
Scheme 3: Biphasic continuous aldol reactions of acetone and various aldehydes.
Scheme 4: Aldol synthesis of 43 in flow using LiHMDS as the base.
Scheme 5: A semi-continuous synthesis of doravirine (49) involving a key aldol reaction.
Scheme 6: Enantioselective aldol reaction using 5-(pyrrolidin-2-yl)tetrazole (51) as catalyst in a microreact...
Scheme 7: Gröger's example of asymmetric aldol reaction in aqueous media.
Figure 6: Immobilised reagent column reactor types.
Scheme 8: Photoinduced thiol–ene coupling preparation of silica-supported 5-(pyrrolidin-2-yl)tetrazole 63 and...
Scheme 9: Continuous-flow approach for enantioselective aldol reactions using the supported catalyst 67.
Scheme 10: Ötvös’ employment of a solid-supported peptide aldol catalyst in flow.
Scheme 11: The use of proline tetrazole packed in a column for aldol reaction between cyclohexanone (65) and 2...
Scheme 12: Schematic diagram of an aminosilane-grafted Si-Zr-Ti/PAI-HF reactor for continuous-flow aldol and n...
Scheme 13: Continuous-flow condensation for the synthesis of the intermediate 76 to nabumetone (77) and Microi...
Scheme 14: Synthesis of ψ-Ionone (80) in continuous-flow via aldol condensation between citral (79) and aceton...
Scheme 15: Synthesis of β-methyl-ionones (83) from citral (79) in flow. The steps are separately described, an...
Scheme 16: Continuous-flow synthesis of 85 from 84 described by Gavriilidis et al.
Scheme 17: Continuous-flow scCO2 apparatus for the synthesis of 2-methylpentanal (87) and the self-condensed u...
Scheme 18: Chen’s two-step flow synthesis of coumarin (90).
Scheme 19: Pechmann condensation for the synthesis of 7-hydroxyxcoumarin (93) in flow. The setup extended to c...
Scheme 20: Synthesis of the dihydrojasmonate 35 exploiting nitro derivative proposed by Ballini et al.
Scheme 21: Silica-supported amines as heterogeneous catalyst for nitroaldol condensation in flow.
Scheme 22: Flow apparatus for the nitroaldol condensation of p-hydroxybenzaldehyde (102) to nitrostyrene 103 a...
Scheme 23: Nitroaldol reaction of 64 to 105 employing a quaternary ammonium functionalised PANF.
Scheme 24: Enantioselective nitroaldol condensation for the synthesis of 108 under flow conditions.
Scheme 25: Enatioselective synthesis of 1,2-aminoalcohol 110 via a copper-catalysed nitroaldol condensation.
Scheme 26: Examples of Knoevenagel condensations applied for fragrance components.
Scheme 27: Flow apparatus for Knoevenagel condensation described in 1989 by Venturello et al.
Scheme 28: Knoevenagel reaction using a coated multichannel membrane microreactor.
Scheme 29: Continuous-flow apparatus for Knoevenagel condensation employing sugar cane bagasse as support deve...
Scheme 30: Knoevenagel reaction for the synthesis of 131–135 in flow using an amine-functionalised silica gel. ...
Scheme 31: Continuous-flow synthesis of compound 137, a key intermediate for the synthesis of pregabalin (138)...
Scheme 32: Continuous solvent-free apparatus applied for the synthesis of compounds 140–143 using a TSE. Throu...
Scheme 33: Lewis et al. developed a spinning disc reactor for Darzens condensation of 144 and a ketone to furn...
Scheme 34: Some key industrial applications of conjugate additions in the F&F industry.
Scheme 35: Continuous-flow synthesis of 4-(2-hydroxyethyl)thiomorpholine 1,1-dioxide (156) via double conjugat...
Scheme 36: Continuous-flow system for Michael addition using CsF on alumina as the catalyst.
Scheme 37: Calcium chloride-catalysed asymmetric Michael addition using an immobilised chiral ligand.
Scheme 38: Continuous multistep synthesis for the preparation of (R)-rolipram (173). Si-NH2: primary amine-fun...
Scheme 39: Continuous-flow Michael addition using ion exchange resin Amberlyst® A26.
Scheme 40: Preparation of the heterogeneous catalyst 181 developed by Paixão et al. exploiting Ugi multicompon...
Scheme 41: Continuous-flow system developed by the Paixão’s group for the preparation of Michael asymmetric ad...
Scheme 42: Continuous-flow synthesis of nitroaldols catalysed by supported catalyst 184 developed by Wennemers...
Scheme 43: Heterogenous polystyrene-supported catalysts developed by Pericàs and co-workers.
Scheme 44: PANF-supported pyrrolidine catalyst for the conjugate addition of cyclohexanone (65) and trans-β-ni...
Scheme 45: Synthesis of (−)-paroxetine precursor 195 developed by Ötvös, Pericàs, and Kappe.
Scheme 46: Continuous-flow approach for the 5-step synthesis of (−)-oseltamivir (201) as devised by Hayashi an...
Scheme 47: Continuous-flow enzyme-catalysed Michael addition.
Scheme 48: Continuous-flow copper-catalysed 1,4 conjugate addition of Grignard reagents to enones. Reprinted w...
Scheme 49: A collection of commonly encountered hydrogenation reactions.
Figure 7: The ThalesNano H-Cube® continuous-flow hydrogenator.
Scheme 50: Chemoselective reduction of an α,β-unsaturated ketone using the H-Cube® reactor.
Scheme 51: Incorporation of Lindlar’s catalyst into the H-Cube® reactor for the reduction of an alkyne.
Scheme 52: Continuous-flow semi-hydrogenation of alkyne 208 to 209 using SACs with H-Cube® system.
Figure 8: The standard setups for tube-in-tube gas–liquid reactor units.
Scheme 53: Homogeneous hydrogenation of olefins using a tube-in-tube reactor setup.
Scheme 54: Recyclable heterogeneous flow hydrogenation system.
Scheme 55: Leadbeater’s reverse tube-in-tube hydrogenation system for olefin reductions.
Scheme 56: a) Hydrogenation using a Pd-immobilised microchannel reactor (MCR) and b) a representation of the i...
Scheme 57: Hydrogenation of alkyne 238 exploiting segmented flow in a Pd-immobilised capillary reactor.
Scheme 58: Continuous hydrogenation system for the preparation of cyrene (241) from (−)-levoglucosenone (240).
Scheme 59: Continuous hydrogenation system based on CSMs developed by Hornung et al.
Scheme 60: Chemoselective reduction of carbonyls (ketones over aldehydes) in flow.
Scheme 61: Continuous system for the semi-hydrogenation of 256 and 258, developed by Galarneau et al.
Scheme 62: Continuous synthesis of biodiesel fuel 261 from lignin-derived furfural acetone (260).
Scheme 63: Continuous synthesis of γ-valerolacetone (263) via CTH developed by Pineda et al.
Scheme 64: Continuous hydrogenation of lignin-derived biomass (products 265, 266, and 267) using a sustainable...
Scheme 65: Ru/C or Rh/C-catalysed hydrogenation of arene in flow as developed by Sajiki et al.
Scheme 66: Polysilane-immobilized Rh–Pt-catalysed hydrogenation of arenes in flow by Kobayashi et al.
Scheme 67: High-pressure in-line mixing of H2 for the asymmetric reduction of 278 at pilot scale with a 73 L p...
Figure 9: Picture of the PFR employed at Eli Lilly & Co. for the continuous hydrogenation of 278 [287]. Reprinted ...
Scheme 68: Continuous-flow asymmetric hydrogenation using Oppolzer's sultam 280 as chiral auxiliary.
Scheme 69: Some examples of industrially important oxidation reactions in the F&F industry. CFL: compact fluor...
Scheme 70: Gold-catalysed heterogeneous oxidation of alcohols in flow.
Scheme 71: Uozumi’s ARP-Pt flow oxidation protocol.
Scheme 72: High-throughput screening of aldehyde oxidation in flow using an in-line GC.
Scheme 73: Permanganate-mediated Nef oxidation of nitroalkanes in flow with the use of in-line sonication to p...
Scheme 74: Continuous-flow aerobic anti-Markovnikov Wacker oxidation.
Scheme 75: Continuous-flow oxidation of 2-benzylpyridine (312) using air as the oxidant.
Scheme 76: Continuous-flow photo-oxygenation of monoterpenes.
Scheme 77: A tubular reactor design for flow photo-oxygenation.
Scheme 78: Glucose oxidase (GOx)-mediated continuous oxidation of glucose using compressed air and the FFMR re...
Scheme 79: Schematic continuous-flow sodium hypochlorite/TEMPO oxidation of alcohols.
Scheme 80: Oxidation using immobilised TEMPO (344) was developed by McQuade et al.
Scheme 81: General protocol for the bleach/catalytic TBAB oxidation of aldehydes and alcohols.
Scheme 82: Continuous-flow PTC-assisted oxidation using hydrogen peroxide. The process was easily scaled up by...
Scheme 83: Continuous-flow epoxidation of cyclohexene (348) and in situ preparation of m-CPBA.
Scheme 84: Continuous-flow epoxidation using DMDO as oxidant.
Scheme 85: Mukayama aerobic epoxidation optimised in flow mode by the Favre-Réguillon group.
Scheme 86: Continuous-flow asymmetric epoxidation of derivatives of 359 exploiting a biomimetic iron catalyst.
Scheme 87: Continuous-flow enzymatic epoxidation of alkenes developed by Watts et al.
Scheme 88: Engineered multichannel microreactor for continuous-flow ozonolysis of 366.
Scheme 89: Continuous-flow synthesis of the vitamin D precursor 368 using multichannel microreactors. MFC: mas...
Scheme 90: Continuous ozonolysis setup used by Kappe et al. for the synthesis of various substrates employing ...
Scheme 91: Continuous-flow apparatus for ozonolysis as developed by Ley et al.
Scheme 92: Continuous-flow ozonolysis for synthesis of vanillin (2) using a film-shear flow reactor.
Scheme 93: Examples of preparative methods for ajoene (386) and allicin (388).
Scheme 94: Continuous-flow oxidation of thioanisole (389) using styrene-based polymer-supported peroxytungstat...
Scheme 95: Continuous oxidation of thiosulfinates using Oxone®-packed reactor.
Scheme 96: Continuous-flow electrochemical oxidation of thioethers.
Scheme 97: Continuous-flow oxidation of 400 to cinnamophenone (235).
Scheme 98: Continuous-flow synthesis of dehydrated material 401 via oxidation of methyl dihydrojasmonate (33).
Scheme 99: Some industrially important transformations involving Grignard reagents.
Scheme 100: Grachev et al. apparatus for continuous preparation of Grignard reagents.
Scheme 101: Example of fluidized Mg bed reactor with NMR spectrometer as on-line monitoring system.
Scheme 102: Continuous-flow synthesis of Grignard reagents and subsequent quenching reaction.
Figure 10: Membrane-based, liquid–liquid separator with integrated pressure control [52]. Adapted with permission ...
Scheme 103: Continuous-flow synthesis of 458, an intermediate to fluconazole (459).
Scheme 104: Continuous-flow synthesis of ketones starting from benzoyl chlorides.
Scheme 105: A Grignard alkylation combining CSTR and PFR technologies with in-line infrared reaction monitoring....
Scheme 106: Continuous-flow preparation of 469 from Grignard addition of methylmagnesium bromide.
Scheme 107: Continuous-flow synthesis of Grignard reagents 471.
Scheme 108: Preparation of the Grignard reagent 471 using CSTR and the continuous process for synthesis of the ...
Scheme 109: Continuous process for carboxylation of Grignard reagents in flow using tube-in-tube technology.
Scheme 110: Continuous synthesis of propargylic alcohols via ethynyl-Grignard reagent.
Scheme 111: Silica-supported catalysed enantioselective arylation of aldehydes using Grignard reagents in flow ...
Scheme 112: Acid-catalysed rearrangement of citral and dehydrolinalool derivatives.
Scheme 113: Continuous stilbene isomerisation with continuous recycling of photoredox catalyst.
Scheme 114: Continuous-flow synthesis of compound 494 as developed by Ley et al.
Scheme 115: Selected industrial applications of DA reaction.
Scheme 116: Multistep flow synthesis of the spirocyclic structure 505 via employing DA cycloaddition.
Scheme 117: Continuous-flow DA reaction developed in a plater flow reactor for the preparation of the adduct 508...
Scheme 118: Continuous-flow DA reaction using a silica-supported imidazolidinone organocatalyst.
Scheme 119: Batch vs flow for the DA reaction of (cyclohexa-1,5-dien-1-yloxy)trimethylsilane (513) with acrylon...
Scheme 120: Continuous-flow DA reaction between 510 and 515 using a shell-core droplet system.
Scheme 121: Continuous-flow synthesis of bicyclic systems from benzyne precursors.
Scheme 122: Continuous-flow synthesis of bicyclic scaffolds 527 and 528 for further development of potential ph...
Scheme 123: Continuous-flow inverse-electron hetero-DA reaction to pyridine derivatives such as 531.
Scheme 124: Comparison between batch and flow for the synthesis of pyrimidinones 532–536 via retro-DA reaction ...
Scheme 125: Continuous-flow coupled with ultrasonic system for preparation of ʟ-ascorbic acid derivatives 539 d...
Scheme 126: Two-step continuous-flow synthesis of triazole 543.
Scheme 127: Continuous-flow preparation of triazoles via CuAAC employing 546-based heterogeneous catalyst.
Scheme 128: Continuous-flow synthesis of compounds 558 through A3-coupling and 560 via AgAAC both employing the...
Scheme 129: Continuous-flow photoinduced [2 + 2] cycloaddition for the preparation of bicyclic derivatives of 5...
Scheme 130: Continuous-flow [2 + 2] and [5 + 2] cycloaddition on large scale employing a flow reactor developed...
Scheme 131: Continuous-flow preparation of the tricyclic structures 573 and 574 starting from pyrrole 570 via [...
Scheme 132: Continuous-flow [2 + 2] photocyclization of cinnamates.
Scheme 133: Continuous-flow preparation of cyclobutane 580 on a 5-plates photoreactor.
Scheme 134: Continuous-flow [2 + 2] photocycloaddition under white LED lamp using heterogeneous PCN as photocat...
Figure 11: Picture of the parallel tube flow reactor (PTFR) "The Firefly" developed by Booker-Milburn et al. a...
Scheme 135: Continuous-flow acid-catalysed [2 + 2] cycloaddition between silyl enol ethers and acrylic esters.
Scheme 136: Continuous synthesis of lactam 602 using glass column reactors.
Scheme 137: In situ generation of ketenes for the Staudinger lactam synthesis developed by Ley and Hafner.
Scheme 138: Application of [2 + 2 + 2] cycloadditions in flow employed by Ley et al.
Scheme 139: Examples of FC reactions applied in F&F industry.
Scheme 140: Continuous-flow synthesis of ibuprofen developed by McQuade et al.
Scheme 141: The FC acylation step of Jamison’s three-step ibuprofen synthesis.
Scheme 142: Synthesis of naphthalene derivative 629 via FC acylation in microreactors.
Scheme 143: Flow system for rapid screening of catalysts and reaction conditions developed by Weber et al.
Scheme 144: Continuous-flow system developed by Buorne, Muller et al. for DSD optimisation of the FC acylation ...
Scheme 145: Continuous-flow FC acylation of alkynes to yield β-chlorovinyl ketones such as 638.
Scheme 146: Continuous-flow synthesis of tonalide (619) developed by Wang et al.
Scheme 147: Continuous-flow preparation of acylated arene such as 290 employing Zr4+-β-zeolite developed by Kob...
Scheme 148: Flow system applied on an Aza-FC reaction catalysed by the thiourea catalyst 648.
Scheme 149: Continuous hydroformylation in scCO2.
Scheme 150: Two-step flow synthesis of aldehyde 655 through a sequential Heck reaction and subsequent hydroform...
Scheme 151: Single-droplet (above) and continuous (below) flow reactors developed by Abolhasani et al. for the ...
Scheme 152: Continuous hydroformylation of 1-dodecene (655) using a PFR-CSTR system developed by Sundmacher et ...
Scheme 153: Continuous-flow synthesis of the aldehyde 660 developed by Eli Lilly & Co. [32]. Adapted with permissio...
Scheme 154: Continuous asymmetric hydroformylation employing heterogenous catalst supported on carbon-based sup...
Scheme 155: Examples of acetylation in F&F industry: synthesis of bornyl (S,R,S-664) and isobornyl (S,S,S-664) ...
Scheme 156: Continuous-flow preparation of bornyl acetate (S,R,S-664) employing the oscillating flow reactor.
Scheme 157: Continuous-flow synthesis of geranyl acetate (666) from acetylation of geraniol (343) developed by ...
Scheme 158: 12-Ttungstosilicic acid-supported silica monolith-catalysed acetylation in flow.
Scheme 159: Continuous-flow preparation of cyclopentenone 676.
Scheme 160: Two-stage synthesis of coumarin (90) via acetylation of salicylaldehyde (88).
Scheme 161: Intensification process for acetylation of 5-methoxytryptamine (677) to melatonin (678) developed b...
Scheme 162: Examples of macrocyclic musky odorants both natural (679–681) and synthetic (682 and 683).
Scheme 163: Flow setup combined with microwave for the synthesis of macrocycle 686 via RCM.
Scheme 164: Continuous synthesis of 2,5-dihydro-1H-pyrroles via ring-closing metathesis.
Scheme 165: Continuous-flow metathesis of 485 developed by Leadbeater et al.
Figure 12: Comparison between RCM performed using different routes for the preparation of 696. On the left the...
Scheme 166: Continuous-flow RCM of 697 employed the solid-supported catalyst 698 developed by Grela, Kirschning...
Scheme 167: Continuous-flow RORCM of cyclooctene employing the silica-absorbed catalyst 700.
Scheme 168: Continuous-flow self-metathesis of methyl oleate (703) employing SILP catalyst 704.
Scheme 169: Flow apparatus for the RCM of 697 using a nanofiltration membrane for the recovery and reuse of the...
Scheme 170: Comparison of loadings between RCMs performed with different routes for the synthesis of 709.
Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233
Graphical Abstract
Figure 1: Some selected self-sorting outcomes and their qualitative and quantitative assessment.
Figure 2: Illustration of an integrative vs a non-integrative self-sorting.
Figure 3: The pH-driven four-component 2-fold completive self-sorting based on host–guest chemistry.
Figure 4: (a) The monomers 5 and 6 and their H-bonding array. (b) The hydrogen-bonded octameric and tetrameri...
Figure 5: (a) Two new Zn4L6-type cages. (b) The encapsulation of C70 induced distinct reconstitutions within ...
Figure 6: The formation of octahedral cages (a) [Co6(10')4]12+ and (b) [Co6(11')4]12+. (c) The 2-fold complet...
Figure 7: Exchange of Ag+ for Au+ ions in poly-NHC ligand-based organometallic assemblies.
Figure 8: The reversible interconversion between the three-component rectangle [Cu4(16)2(17)2]4+ and the four...
Figure 9: a) Chemical structure of the monomer 20 with its quadruple hydrogen-bonding array and a metal-affin...
Figure 10: Communication between the nanoswitch 21 and the supramolecular assemblies [Cu4(22)2(24)2]4+ or [Cu6(...
Figure 11: (a) The chemical structures and cartoon representations of the switch 25, the decks 26 and 27, and ...
Figure 12: Double self-sorting leads to a catalytic machinery in SelfSORT-II, in which the 46 kHz-nanorotor ac...
Figure 13: ON/OFF control of a networked catalytic catch–release system.
Figure 14: A multicomponent information system for the reversible reconfiguration of switchable dual catalysis....
Figure 15: a) The chemically fueled cascaded ion translocation, monitored by distinct emission colors. b) Work...
Figure 16: Cyclic metallosupramolecular transformations.
Figure 17: Fully reversible multiple-state rearrangement of metallosupramolecular architectures depending upon...
Figure 18: The selective encapsulation and sequential release of guests in a self-sorted mixture of three tetr...
Figure 19: Two catalytic reactions are alternately controlled by a toggle nanoswitch.
Figure 20: A biped walking along a tetrahedral track and unfolding its catalytic action. Adapted with permissi...
Figure 21: A three state supramolecular AND logic gate.
Figure 22: Four-component nanorotor and its catalytic activity. Adapted with permission from (Biswas, P. K.; S...
Beilstein J. Org. Chem. 2020, 16, 2080–2086, doi:10.3762/bjoc.16.175
Graphical Abstract
Scheme 1: Simplified mechanism of the hydrohydrazidation (NuH= ArCONHNH2) of alkynes.
Scheme 2: [(NHC)Au(NTf2)] complexes tested in hydrohydrazidation reactions of phenylacetylene.
Scheme 3: Hydrohydrazidation of terminal alkynes in chlorobenzene and anisole using complex 1 (first line sol...
Scheme 4: Hydrohydrazidation of internal alkynes in chlorobenzene and anisole using complex 1. Reaction tempe...
Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159
Graphical Abstract
Scheme 1: Synthesis of NHC-supported catalysts.
Scheme 2: Negishi benchmark reaction.
Figure 1: Negishi reaction catalyzed by immobilized NHC–Pd complexes. Conditions: methyl 4-bromobenzoate (0.2...
Scheme 3: Synthesis of immobilized NHC–Pd–RuPhos.
Figure 2: Negishi model reaction between 5 and 6 under flow conditions catalyzed by 4b. V = 0.535 mL, 363 mg ...
Figure 3: Negishi model reaction under flow conditions catalyzed by 8a. V = 2.9 mL, 1.25 g of catalyst, resid...
Figure 4: Negishi reaction between 5 and 6 catalyzed by 8a in the presence of SILLPs. a) Yield (%) vs time fo...
Figure 5: TEM images of the polymers after the Negishi reaction between 5 and 6. a) 8a, bar scale 20 nm, PdNP...
Scheme 4: Pd species immobilized onto SILLPs. i) 1 g SILLP 10, 100 mg PdCl2 in milli-Q® water (100 mL 1% HCl,...
Figure 6: Negishi reaction between 5 and 6 catalyzed by 11. 1 equiv methyl 4-bromobenzoate (6, 0.25 mmol), 2 ...
Figure 7: Negishi reaction between 5 and 6 under flow conditions catalyzed by 8a in the presence of a scaveng...
Figure 8: Effect of the structure of the SILLP scavenger for the Negishi reaction between 5 and 6 under flow ...
Figure 9: TEM images of the polymer after the Negishi reaction between 5 and 6 under flow conditions. a) 8a + ...
Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67
Graphical Abstract
Scheme 1: Pharmaceuticals possessing a silicon or boron atom.
Scheme 2: The first Cu-catalyzed C(sp3)–Si bond formation.
Scheme 3: Conversion of benzylic phosphate 6 to the corresponding silane.
Scheme 4: Conversion of alkyl triflates to alkylsilanes.
Scheme 5: Conversion of secondary alkyl triflates to alkylsilanes.
Scheme 6: Conversion of alkyl iodides to alkylsilanes.
Scheme 7: Trapping of intermediate radical through cascade reaction.
Scheme 8: Radical pathway for conversion of alkyl iodides to alkylsilanes.
Scheme 9: Conversion of alkyl ester of N-hydroxyphthalimide to alkylsilanes.
Scheme 10: Conversion of gem-dibromides to bis-silylalkanes.
Scheme 11: Conversion of imines to α-silylated amines (A) and the reaction pathway (B).
Scheme 12: Conversion of N-tosylimines to α-silylated amines.
Scheme 13: Screening of diamine ligands.
Scheme 14: Conversion of N-tert-butylsulfonylimines to α-silylated amines.
Scheme 15: Conversion of aldimines to nonracemic α-silylated amines.
Scheme 16: Conversion of N-tosylimines to α-silylated amines.
Scheme 17: Reaction pathway [A] and conversion of aldehydes to α-silylated alcohols [B].
Scheme 18: Conversion of aldehydes to benzhydryl silyl ethers.
Scheme 19: Conversion of ketones to 1,2-diols (A) and conversion of imines to 1,2-amino alcohols (B).
Scheme 20: Ligand screening (A) and conversion of aldehydes to α-silylated alcohols (B).
Scheme 21: Conversion of aldehydes to α-silylated alcohols.
Scheme 22: 1,4-Additions to α,β-unsaturated ketones.
Scheme 23: 1,4-Additions to unsaturated ketones to give β-silylated derivatives.
Scheme 24: Additions onto α,β-unsaturated lactones to give β-silylated lactones.
Scheme 25: Conversion of α,β-unsaturated to β-silylated lactams.
Scheme 26: Conversion of N-arylacrylamides to silylated oxindoles.
Scheme 27: Conversion of α,β-unsaturated carbonyl compounds to silylated tert-butylperoxides.
Scheme 28: Catalytic cycle for Cu(I) catalyzed α,β-unsaturated compounds.
Scheme 29: Conversion of p-quinone methides to benzylic silanes.
Scheme 30: Conversion of α,β-unsaturated ketimines to regio- and stereocontrolled allylic silanes.
Scheme 31: Conversion of α,β-unsaturated ketimines to enantioenriched allylic silanes.
Scheme 32: Regioselective conversion of dienedioates to allylic silanes.
Scheme 33: Conversion of alkenyl-substituted azaarenes to β-silylated adducts.
Scheme 34: Conversion of conjugated benzoxazoles to enantioenriched β-silylated adducts.
Scheme 35: Conversion of α,β-unsaturated carbonyl indoles to α-silylated N-alkylated indoles.
Scheme 36: Conversion of β-amidoacrylates to α-aminosilanes.
Scheme 37: Conversion of α,β-unsaturated ketones to enantioenriched β-silylated ketones, nitriles, and nitro d...
Scheme 38: Regio-divergent silacarboxylation of allenes.
Scheme 39: Silylation of diazocarbonyl compounds, (A) asymmetric and (B) racemic.
Scheme 40: Enantioselective hydrosilylation of alkenes.
Scheme 41: Conversion of 3-acylindoles to indolino-silanes.
Scheme 42: Proposed mechanism for the silylation of 3-acylindoles.
Scheme 43: Silyation of N-chlorosulfonamides.
Scheme 44: Conversion of acyl silanes to α-silyl alcohols.
Scheme 45: Conversion of N-tosylaziridines to β-silylated N-tosylamines.
Scheme 46: Conversion of N-tosylaziridines to silylated N-tosylamines.
Scheme 47: Conversion of 3,3-disubstituted cyclopropenes to silylated cyclopropanes.
Scheme 48: Conversion of conjugated enynes to 1,3-bis(silyl)propenes.
Scheme 49: Proposed sequence for the Cu-catalyzed borylation of substituted alkenes.
Scheme 50: Cu-catalyzed synthesis of nonracemic allylic boronates.
Scheme 51: Cu–NHC catalyzed synthesis of α-substituted allylboronates.
Scheme 52: Synthesis of α-chiral (γ-alkoxyallyl)boronates.
Scheme 53: Cu-mediated formation of nonracemic cis- or trans- 2-substituted cyclopropylboronates.
Scheme 54: Cu-catalyzed synthesis of γ,γ-gem-difluoroallylboronates.
Scheme 55: Cu-catalyzed hydrofunctionalization of internal alkenes and vinylarenes.
Scheme 56: Cu-catalyzed Markovnikov and anti-Markovnikov borylation of alkenes.
Scheme 57: Cu-catalyzed borylation/ortho-cyanation/Cope rearrangement.
Scheme 58: Borylfluoromethylation of alkenes.
Scheme 59: Cu-catalyzed synthesis of tertiary nonracemic alcohols.
Scheme 60: Synthesis of densely functionalized and synthetically versatile 1,2- or 4,3-borocyanated 1,3-butadi...
Scheme 61: Cu-catalyzed trifunctionalization of allenes.
Scheme 62: Cu-catalyzed selective arylborylation of arenes.
Scheme 63: Asymmetric borylative coupling between styrenes and imines.
Scheme 64: Regio-divergent aminoboration of unactivated terminal alkenes.
Scheme 65: Cu-catalyzed 1,4-borylation of α,β-unsaturated ketones.
Scheme 66: Cu-catalyzed protodeboronation of α,β-unsaturated ketones.
Scheme 67: Cu-catalyzed β-borylation of α,β-unsaturated imines.
Scheme 68: Cu-catalyzed synthesis of β-trifluoroborato carbonyl compounds.
Scheme 69: Asymmetric 1,4-borylation of α,β-unsaturated carbonyl compounds.
Scheme 70: Cu-catalyzed ACB and ACA reactions of α,β-unsaturated 2-acyl-N-methylimidazoles.
Scheme 71: Cu-catalyzed diborylation of aldehydes.
Scheme 72: Umpolung pathway for chiral, nonracemic tertiary alcohol synthesis (top) and proposed mechanism for...
Scheme 73: Cu-catalyzed synthesis of α-hydroxyboronates.
Scheme 74: Cu-catalyzed borylation of ketones.
Scheme 75: Cu-catalyzed borylation of unactivated alkyl halides.
Scheme 76: Cu-catalyzed borylation of allylic difluorides.
Scheme 77: Cu-catalyzed borylation of cyclic and acyclic alkyl halides.
Scheme 78: Cu-catalyzed borylation of unactivated alkyl chlorides and bromides.
Scheme 79: Cu-catalyzed decarboxylative borylation of carboxylic acids.
Scheme 80: Cu-catalyzed borylation of benzylic, allylic, and propargylic alcohols.
Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50
Beilstein J. Org. Chem. 2020, 16, 482–491, doi:10.3762/bjoc.16.43
Graphical Abstract
Scheme 1: Formation of sulfonyltriazoles and sulfonamidines.
Figure 1: Catalytic systems used in this study.
Scheme 2: Synthetic access to complexes 4–6 [30].
Scheme 3: Variation of sulfonylazides. Reaction conditions: phenylacetylene (0.5 mmol), sulfonyl azide (0.6 m...
Scheme 4: Variation of alkynes. Reaction conditions: alkyne (0.5 mmol), tosyl azide (0.6 mmol), diisopropylam...
Scheme 5: Variation of the amine substrate. Reaction conditions: phenylacetylene (0.5 mmol), tosyl azide (0.6...
Scheme 6: Reactivity of “non-sulfonyl” azide [33]. Reaction conditions: phenylacetylene (0.5 mmol), benzyl azide ...
Scheme 7: Reactivity of diphenylphosphoryl azide. Reaction conditions: phenylacetylene (0.5 mmol), diphenylph...
Scheme 8: Proposed mechanism for the formation of sulfonamidine.
Scheme 9: Stoichiometric reaction between 6 and 8.
Scheme 10: Synthesis of copper-acetylide intermediate A via [Cu(Cl)(Triaz)].
Scheme 11: Catalytic reaction involving copper-acetylide complex A.
Beilstein J. Org. Chem. 2020, 16, 185–189, doi:10.3762/bjoc.16.21
Graphical Abstract
Scheme 1: Our strategy.
Scheme 2: Allylic cross-coupling using aldehydes as α-alkoxyalkyl anions.
Scheme 3: Substrate scope and reaction conditions. a) reactions were carried out with 1 (0.4 mmol), 2 (0.2 mm...
Scheme 4: Stoichiometric reaction.
Scheme 5: Possible pathway.
Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165
Graphical Abstract
Figure 1: Various drugs having IP nucleus.
Figure 2: Participation percentage of various TMs for the syntheses of IPs.
Scheme 1: CuI–NaHSO4·SiO2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 2: Experimental examination of reaction conditions.
Scheme 3: One-pot tandem reaction for the synthesis of 2-haloimidazopyridines.
Scheme 4: Mechanistic scheme for the synthesis of 2-haloimidazopyridine.
Scheme 5: Copper-MOF-catalyzed three-component reaction (3-CR) for imidazo[1,2-a]pyridines.
Scheme 6: Mechanism for copper-MOF-driven synthesis.
Scheme 7: Heterogeneous synthesis via titania-supported CuCl2.
Scheme 8: Mechanism involving oxidative C–H functionalization.
Scheme 9: Heterogeneous synthesis of IPs.
Scheme 10: One-pot regiospecific synthesis of imidazo[1,2-a]pyridines.
Scheme 11: Vinyl azide as an unprecedented substrate for imidazo[1,2-a]pyridines.
Scheme 12: Radical pathway.
Scheme 13: Cu(I)-catalyzed transannulation approach for imidazo[1,5-a]pyridines.
Scheme 14: Plausible radical pathway for the synthesis of imidazo[1,5-a]pyridines.
Scheme 15: A solvent-free domino reaction for imidazo[1,2-a]pyridines.
Scheme 16: Cu-NPs-mediated synthesis of imidazo[1,2-a]pyridines.
Scheme 17: CuI-catalyzed synthesis of isoxazolylimidazo[1,2-a]pyridines.
Scheme 18: Functionalization of 4-bromo derivative via Sonogashira coupling reaction.
Scheme 19: A plausible reaction pathway.
Scheme 20: Cu(I)-catalyzed intramolecular oxidative C–H amidation reaction.
Scheme 21: One-pot synthetic reaction for imidazo[1,2-a]pyridine.
Scheme 22: Plausible reaction mechanism.
Scheme 23: Cu(OAc)2-promoted synthesis of imidazo[1,2-a]pyridines.
Scheme 24: Mechanism for aminomethylation/cycloisomerization of propiolates with imines.
Scheme 25: Three-component synthesis of imidazo[1,2-a]pyridines.
Figure 3: Scope of pyridin-2(1H)-ones and acetophenones.
Scheme 26: CuO NPS-promoted A3 coupling reaction.
Scheme 27: Cu(II)-catalyzed C–N bond formation reaction.
Scheme 28: Mechanism involving Chan–Lam/Ullmann coupling.
Scheme 29: Synthesis of formyl-substituted imidazo[1,2-a]pyridines.
Scheme 30: A tandem sp3 C–H amination reaction.
Scheme 31: Probable mechanistic approach.
Scheme 32: Dual catalytic system for imidazo[1,2-a]pyridines.
Scheme 33: Tentative mechanism.
Scheme 34: CuO/CuAl2O4/ᴅ-glucose-promoted 3-CCR.
Scheme 35: A tandem CuOx/OMS-2-based synthetic strategy.
Figure 4: Biomimetic catalytic oxidation in the presence of electron-transfer mediators (ETMs).
Scheme 36: Control experiment.
Scheme 37: Copper-catalyzed C(sp3)–H aminatin reaction.
Scheme 38: Reaction of secondary amines.
Scheme 39: Probable mechanistic pathway.
Scheme 40: Coupling reaction of α-azidoketones.
Scheme 41: Probable pathway.
Scheme 42: Probable mechanism with free energy calculations.
Scheme 43: MCR for cyanated IP synthesis.
Scheme 44: Substrate scope for the reaction.
Scheme 45: Reaction mechanism.
Scheme 46: Probable mechanistic pathway for Cu/ZnAl2O4-catalyzed reaction.
Scheme 47: Copper-catalyzed double oxidative C–H amination reaction.
Scheme 48: Application towards different coupling reactions.
Scheme 49: Reaction mechanism.
Scheme 50: Condensation–cyclization approach for the synthesis of 1,3-diarylated imidazo[1,5-a]pyridines.
Scheme 51: Optimized reaction conditions.
Scheme 52: One-pot 2-CR.
Scheme 53: One-pot 3-CR without the isolation of chalcone.
Scheme 54: Copper–Pybox-catalyzed cyclization reaction.
Scheme 55: Mechanistic pathway catalyzed by Cu–Pybox complex.
Scheme 56: Cu(II)-promoted C(sp3)-H amination reaction.
Scheme 57: Wider substrate applicability for the reaction.
Scheme 58: Plausible reaction mechanism.
Scheme 59: CuI assisted C–N cross-coupling reaction.
Scheme 60: Probable reaction mechanism involving sp3 C–H amination.
Scheme 61: One-pot MCR-catalyzed by CoFe2O4/CNT-Cu.
Scheme 62: Mechanistic pathway.
Scheme 63: Synthetic scheme for 3-nitroimidazo[1,2-a]pyridines.
Scheme 64: Plausible mechanism for CuBr-catalyzed reaction.
Scheme 65: Regioselective synthesis of halo-substituted imidazo[1,2-a]pyridines.
Scheme 66: Synthesis of 2-phenylimidazo[1,2-a]pyridines.
Scheme 67: Synthesis of diarylated compounds.
Scheme 68: CuBr2-mediated one-pot two-component oxidative coupling reaction.
Scheme 69: Decarboxylative cyclization route to synthesize 1,3-diarylimidazo[1,5-a]pyridines.
Scheme 70: Mechanistic pathway.
Scheme 71: C–H functionalization reaction of enamines to produce diversified heterocycles.
Scheme 72: A plausible mechanism.
Scheme 73: CuI-promoted aerobic oxidative cyclization reaction of ketoxime acetates and pyridines.
Scheme 74: CuI-catalyzed pathway for the formation of imidazo[1,2-a]pyridine.
Scheme 75: Mechanistic pathway.
Scheme 76: Mechanistic rationale for the synthesis of products.
Scheme 77: Copper-catalyzed synthesis of vinyloxy-IP.
Scheme 78: Regioselective product formation with propiolates.
Scheme 79: Proposed mechanism for vinyloxy-IP formation.
Scheme 80: Regioselective synthesis of 3-hetero-substituted imidazo[1,2-a]pyridines with different reaction su...
Scheme 81: Mechanistic pathway.
Scheme 82: CuI-mediated synthesis of 3-formylimidazo[1,2-a]pyridines.
Scheme 83: Radical pathway for 3-formylated IP synthesis.
Scheme 84: Pd-catalyzed urea-cyclization reaction for IPs.
Scheme 85: Pd-catalyzed one-pot-tandem amination and intramolecular amidation reaction.
Figure 5: Scope of aniline nucleophiles.
Scheme 86: Pd–Cu-catalyzed Sonogashira coupling reaction.
Scheme 87: One-pot amide coupling reaction for the synthesis of imidazo[4,5-b]pyridines.
Scheme 88: Urea cyclization reaction for the synthesis of two series of pyridines.
Scheme 89: Amidation reaction for the synthesis of imidazo[4,5-b]pyridines.
Figure 6: Amide scope.
Scheme 90: Pd NPs-catalyzed 3-component reaction for the synthesis of 2,3-diarylated IPs.
Scheme 91: Plausible mechanistic pathway for Pd NPs-catalyzed MCR.
Scheme 92: Synthesis of chromenoannulated imidazo[1,2-a]pyridines.
Scheme 93: Mechanism for the synthesis of chromeno-annulated IPs.
Scheme 94: Zinc oxide NRs-catalyzed synthesis of imidazo[1,2-a]azines/diazines.
Scheme 95: Zinc oxide-catalyzed isocyanide based GBB reaction.
Scheme 96: Reaction pathway for ZnO-catalyzed GBB reaction.
Scheme 97: Mechanistic pathway.
Scheme 98: ZnO NRs-catalyzed MCR for the synthesis of imidazo[1,2-a]azines.
Scheme 99: Ugi type GBB three-component reaction.
Scheme 100: Magnetic NPs-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 101: Regioselective synthesis of 2-alkoxyimidazo[1,2-a]pyridines catalyzed by Fe-SBA-15.
Scheme 102: Plausible mechanistic pathway for the synthesis of 2-alkoxyimidazopyridine.
Scheme 103: Iron-catalyzed synthetic approach.
Scheme 104: Iron-catalyzed aminooxygenation reaction.
Scheme 105: Mechanistic pathway.
Scheme 106: Rh(III)-catalyzed double C–H activation of 2-substituted imidazoles and alkynes.
Scheme 107: Plausible reaction mechanism.
Scheme 108: Rh(III)-catalyzed non-aromatic C(sp2)–H bond activation–functionalization for the synthesis of imid...
Scheme 109: Reactivity and selectivity of different substrates.
Scheme 110: Rh-catalyzed direct C–H alkynylation by Li et al.
Scheme 111: Suggested radical mechanism.
Scheme 112: Scandium(III)triflate-catalyzed one-pot reaction and its mechanism for the synthesis of benzimidazo...
Scheme 113: RuCl3-assisted Ugi-type Groebke–Blackburn condensation reaction.
Scheme 114: C-3 aroylation via Ru-catalyzed two-component reaction.
Scheme 115: Regioselective synthetic mechanism.
Scheme 116: La(III)-catalyzed one-pot GBB reaction.
Scheme 117: Mechanistic approach for the synthesis of imidazo[1,2-a]pyridines.
Scheme 118: Synthesis of imidazo[1,2-a]pyridine using LaMnO3 NPs under neat conditions.
Scheme 119: Mechanistic approach.
Scheme 120: One-pot 3-CR for regioselective synthesis of 2-alkoxy-3-arylimidazo[1,2-a]pyridines.
Scheme 121: Formation of two possible products under optimization of the catalysts.
Scheme 122: Mechanistic strategy for NiFe2O4-catalyzed reaction.
Scheme 123: Two-component reaction for synthesizing imidazodipyridiniums.
Scheme 124: Mechanistic scheme for the synthesis of imidazodipyridiniums.
Scheme 125: CuI-catalyzed arylation of imidazo[1,2-a]pyridines.
Scheme 126: Mechanism for arylation reaction.
Scheme 127: Cupric acetate-catalyzed double carbonylation approach.
Scheme 128: Radical mechanism for double carbonylation of IP.
Scheme 129: C–S bond formation reaction catalyzed by cupric acetate.
Scheme 130: Cupric acetate-catalyzed C-3 formylation approach.
Scheme 131: Control experiments for signifying the role of DMSO and oxygen.
Scheme 132: Mechanism pathway.
Scheme 133: Copper bromide-catalyzed CDC reaction.
Scheme 134: Extension of the substrate scope.
Scheme 135: Plausible radical pathway.
Scheme 136: Transannulation reaction for the synthesis of imidazo[1,5-a]pyridines.
Scheme 137: Plausible reaction pathway for denitrogenative transannulation.
Scheme 138: Cupric acetate-catalyzed C-3 carbonylation reaction.
Scheme 139: Plausible mechanism for regioselective C-3 carbonylation.
Scheme 140: Alkynylation reaction at C-2 of 3H-imidazo[4,5-b]pyridines.
Scheme 141: Two-way mechanism for C-2 alkynylation of 3H-imidazo[4,5-b]pyridines.
Scheme 142: Palladium-catalyzed SCCR approach.
Scheme 143: Palladium-catalyzed Suzuki coupling reaction.
Scheme 144: Reaction mechanism.
Scheme 145: A phosphine free palladium-catalyzed synthesis of C-3 arylated imidazopyridines.
Scheme 146: Palladium-mediated Buchwald–Hartwig cross-coupling reaction.
Figure 7: Structure of the ligands optimized.
Scheme 147: Palladium acetate-catalyzed direct arylation of imidazo[1,2-a]pyridines.
Scheme 148: Palladium acetate-catalyzed mechanistic pathway.
Scheme 149: Palladium acetate-catalyzed regioselective arylation reported by Liu and Zhan.
Scheme 150: Mechanism for selective C-3 arylation of IP.
Scheme 151: Pd(II)-catalyzed alkenylation reaction with styrenes.
Scheme 152: Pd(II)-catalyzed alkenylation reaction with acrylates.
Scheme 153: A two way mechanism.
Scheme 154: Double C–H activation reaction catalyzed by Pd(OAc)2.
Scheme 155: Probable mechanism.
Scheme 156: Palladium-catalyzed decarboxylative coupling.
Scheme 157: Mechanistic cycle for decarboxylative arylation reaction.
Scheme 158: Ligand-free approach for arylation of imidazo[1,2-a]pyridine-3-carboxylic acids.
Scheme 159: Mechanism for ligandless arylation reaction.
Scheme 160: NHC-Pd(II) complex assisted arylation reaction.
Scheme 161: C-3 arylation of imidazo[1,2-a]pyridines with aryl bromides catalyzed by Pd(OAc)2.
Scheme 162: Pd(II)-catalyzed C-3 arylations with aryl tosylates and mesylates.
Scheme 163: CDC reaction for the synthesis of imidazo[1,2-a]pyridines.
Scheme 164: Plausible reaction mechanism for Pd(OAc)2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 165: Pd-catalyzed C–H amination reaction.
Scheme 166: Mechanism for C–H amination reaction.
Scheme 167: One-pot synthesis for 3,6-di- or 2,3,6-tri(hetero)arylimidazo[1,2-a]pyridines.
Scheme 168: C–H/C–H cross-coupling reaction of IPs and azoles catalyzed by Pd(II).
Scheme 169: Mechanistic cycle.
Scheme 170: Rh-catalyzed C–H arylation reaction.
Scheme 171: Mechanistic pathway for C–H arylation of imidazo[1,2-a]pyridine.
Scheme 172: Rh(III)-catalyzed double C–H activation of 2-phenylimidazo[1,2-a]pyridines and alkynes.
Scheme 173: Rh(III)-catalyzed mechanistic pathway.
Scheme 174: Rh(III)-mediated oxidative coupling reaction.
Scheme 175: Reactions showing functionalization of the product obtained by the group of Kotla.
Scheme 176: Mechanism for Rh(III)-catalyzed oxidative coupling reaction.
Scheme 177: Rh(III)-catalyzed C–H activation reaction.
Scheme 178: Mechanistic cycle.
Scheme 179: Annulation reactions of 2-arylimidazo[1,2-a]pyridines and alkynes.
Scheme 180: Two-way reaction mechanism for annulations reaction.
Scheme 181: [RuCl2(p-cymene)]2-catalyzed C–C bond formation reaction.
Scheme 182: Reported reaction mechanism.
Scheme 183: Fe(III) catalyzed C-3 formylation approach.
Scheme 184: SET mechanism-catalyzed by Fe(III).
Scheme 185: Ni(dpp)Cl2-catalyzed KTC coupling.
Scheme 186: Pd-catalyzed SM coupling.
Scheme 187: Vanadium-catalyzed coupling of IP and NMO.
Scheme 188: Mechanistic cycle.
Scheme 189: Selective C3/C5–H bond functionalizations by mono and bimetallic systems.
Scheme 190: rGO-Ni@Pd-catalyzed C–H bond arylation of imidazo[1,2-a]pyridine.
Scheme 191: Mechanistic pathway for heterogeneously catalyzed arylation reaction.
Scheme 192: Zinc triflate-catalyzed coupling reaction of substituted propargyl alcohols.
Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73
Graphical Abstract
Figure 1: Commercially available ruthenium catalysts for metathesis reactions.
Figure 2: Retrosynthesis of the ruthenium catalysts.
Scheme 1: Efficient multigram synthesis of N,N-dialkyl-2-vinylbenzylamines 4 (R1X = Me2SO4, Et2SO4 or BnCl, s...
Scheme 2: Synthesis of N-(2-ethenylbenzyl)heterocycles 5.
Scheme 3: Synthesis of N-monoalkyl-2-vinylbenzylamine 7.
Scheme 4: Synthesis of Hoveyda–Grubbs-type catalysts 11.
Scheme 5: Synthesis of the “chloroform adduct” 9.
Figure 3: Selected X-ray data for ruthenium complexes 11a–c. All hydrogen atoms were deleted for clarity (exc...
Scheme 6: Catalytic activity of compounds 11 in the metathesis reactions.
Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39
Graphical Abstract
Scheme 1: Most common metathesis reactions. Ring-opening metathesis polymerization (ROMP), acyclic diene meta...
Scheme 2: Catalytic cycle for metathesis proposed by Chauvin.
Figure 1: Some of the most representative catalysts for aqueous metathesis. a) Well-defined ruthenium catalys...
Scheme 3: First aqueous ROMP reactions catalyzed by ruthenium(III) salts.
Scheme 4: Degradation pathway of first generation Grubbs catalyst (G-I) in methanol.
Scheme 5: Synthesis of Blechert-type catalysts 19 and 20.
Figure 2: Chemical structure and components of amphiphilic molecule PTS and derivatives.
Scheme 6: RCM of selected substrates in the presence of the surfactant PTS. Conditionsa: The reaction was car...
Scheme 7: RCM reactions of substrates 31 and 33 with the encapsulated G-II catalyst.
Scheme 8: Living ROMP of norbornene derivatives 35 and 36 with phosphine-based catalysts bearing quaternary a...
Scheme 9: Synthesis of water-soluble catalysts 3 and 4 bearing quaternary ammonium tags.
Scheme 10: In situ formation of catalyst 5 bearing a quaternary ammonium group.
Scheme 11: Catalyst recycling of an ammonium-bearing catalyst.
Scheme 12: Removal of the water-soluble catalyst 12 through host–guest interaction with silica-gel-supported β...
Scheme 13: Selection of artificial metathases reported by Ward and co-workers (ArM 1 based on biotin–(strept)a...
Figure 3: In vivo metathesis with an artificial metalloenzyme based on the biotin–streptavidin technology.
Scheme 14: Artificial metathase based on covalent anchoring approach. α-Chymotrypsin interacts with catalyst 66...
Scheme 15: Assembling an artificial metathase (ArM 4) based on the small heat shock protein from M. Jannaschii...
Scheme 16: Artificial metathases based on cavity-size engineered β-barrel protein nitrobindin (NB4exp). The HG...
Scheme 17: Artificial metathase based on cutinase (ArM 8) and resulting metathesis activities.
Scheme 18: Site-specific modification of proteins via aqueous cross-metathesis. The protein structure is based...
Scheme 19: a) Allyl homocysteine (Ahc)-modified proteins as CM substrates. b) Incorporation of Ahc in the Fc p...
Scheme 20: On-DNA cross-metathesis reaction of allyl sulfide 99.
Scheme 21: Preparation of BODIPY-containing profluorescent probes 102 and 104.
Scheme 22: Metathesis-based ethylene detection in live cells.
Scheme 23: First example of stapled peptides via olefin metathesis.
Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19
Graphical Abstract
Figure 1: Structures of Grubbs 1 (1) and 2 (2) precatalysts.
Scheme 1: Design concepts for ruthenium alkylidene precatalysts [3].
Figure 2: Structures of Grubbs 1-type (3) and 2-type (4) pyridinyl-alcoholato precatalysts.
Figure 3: Structures of Grubbs 2-type (5) pyridinyl-alcoholato precatalysts.
Figure 4: Structures of pyridinyl-substituted Grubbs 2-type pyridinyl-alcoholato precatalysts.
Figure 5: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 6: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 7: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 8: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 9: Geometry-optimised structures of precatalyst 9, 6 and 8.
Figure 10: An illustration of the envisaged methoxy oxygen lone pair-aromatic π-electron interaction.
Figure 11: Influence of precatalysts 6–9 and 5d on the (a) conversion of 1-octene and (b) ln([n%1-octene]) ver...
Figure 12: 1H NMR spectra of the carbene-Hα region at different time intervals of the 1-octene/7 reaction mixt...
Figure 13: 1H NMR spectra of the Hα region of the pyridine ring of the 1-octene/7 reaction mixture in toluene-d...
Scheme 2: Synthesis of pyridinyl-alcohol ligands and Grubbs 2-type pyridinyl-alcoholato complexes.
Beilstein J. Org. Chem. 2019, 15, 160–166, doi:10.3762/bjoc.15.16
Graphical Abstract
Figure 1: Structures of the Ru-based catalysts used in this study.
Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292
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.
Beilstein J. Org. Chem. 2018, 14, 2999–3010, doi:10.3762/bjoc.14.279
Graphical Abstract
Scheme 1: Synthesis of first Ru-dithiolate metathesis catalysts.
Figure 1: Most efficient Ru-dithiolate catalysts for stereoretentive olefin metathesis with Z- and E-alkenes ...
Figure 2: Selected examples of sterically or electronically modified ruthenium dithiolate complexes.
Figure 3: Model for stereoretentive metathesis proposed by Pederson and Grubbs [3].
Figure 4: Decrease in the benzylidene signal over time upon reaction with (E)-2-hexenyl acetate.
Scheme 2: Selected applications, part 1.
Scheme 3: Selected applications, part 2.
Figure 5: Catalyst loading required for different types of metathesis reactions.
Scheme 4: Proposed catalyst decomposition pathway occurring via attack of the electron-rich sulfide into meth...
Scheme 5: In situ methylene capping strategy for stereoretentive metathesis.
Scheme 6: Stereoretentive cross-metathesis with (Z)-butene (Z-25) as in situ methylene capping agent; selecte...
Scheme 7: Cross metathesis with Z- and E-trisubstituted allylic alcohols.
Scheme 8: In situ synthesis of Ru-3 and application thereof in the cross-metathesis of 12 and 50.
Figure 6: Examples of biologically active and fragrance molecules synthesized by stereoretentive metathesis.
Beilstein J. Org. Chem. 2018, 14, 2956–2963, doi:10.3762/bjoc.14.275
Graphical Abstract
Scheme 1: Catalysts studied by DFT calculations.
Scheme 2: Precatalyst initiation in olefin metathesis (L = NHC ligand).
Figure 1: Topographic steric maps (plane xy) of the NHC ligands of species I for the studied SIMes–Ru complex...
Figure 2: Intermediate II for catalysts a) 1 and b) 5 (important bond lengths are given in Å).
Beilstein J. Org. Chem. 2018, 14, 2872–2880, doi:10.3762/bjoc.14.266
Graphical Abstract
Scheme 1: NHC’s and their ruthenium complexes studied in this work; L = carbene 1, 2 or 3.
Scheme 2: Schematic representation of carbene dimerization and atom numbering scheme used throughout this wor...
Scheme 3: Dissociative mechanism of initiation for Grubbs-like 1–3-GrI and M1 indenylidene type complexes 1–3...
Scheme 4: Dissociative mechanism of initiation of 2nd generation Grubbs-like saturated 1–3-GrII and unsaturat...
Scheme 5: Dissociative mechanism of activation for complexes 1–3-Hov; L = carbene 1, 2 or 3.
Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265
Graphical Abstract
Scheme 1: Left: Mechanism of the olefin metathesis reaction postulated by Chauvin [2]. Right: Potential influenc...
Scheme 2: (i) Ring-opening metathesis polymerization (ROMP), (ii) ring-closing metathesis (RCM) and (iii) cro...
Figure 1: Common anchoring strategies for metal-complex or metal ion incorporation into protein scaffolds.
Scheme 3: Biotinylated GH-type catalysts for conjugation to (strept)avidin and their catalyzed ring-closing m...
Scheme 4: Whole-cell artificial metatheases designed by Ward et al. [47].
Scheme 5: Coupling of GH-type catalysts Ru-4/5/6 to NB4 or NB11.
Scheme 6: Anchoring and refolding of GH-type catalysts Ru-4/5/6 to FhuA.
Figure 2: Top: NB4 (PDB 3WJB); bottom: NB4exp. Highlighted in blue are the additional two β-sheets. Highlight...