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Search for "lithium chloride" in Full Text gives 21 result(s) in Beilstein Journal of Organic Chemistry.
Radical ligand transfer: a general strategy for radical functionalization
- David T. Nemoto Jr,
- Kang-Jie Bian,
- Shih-Chieh Kao and
- Julian G. West
Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90
- various acids with lead(IV) tetraacetate in the presence of lithium chloride (Scheme 4) [40][41]. Nucleophilic lithium chloride was used as the chlorine atom source for this transformation. In the representative scope of this transformation, primary and secondary chlorides could be formed in relatively
Graphical Abstract
Scheme 1: Overview of the RLT mechanism in nature and in literature. I: The radical rebound mechanism in cyto...
Scheme 2: Areas of recent work on RLT development and application in catalysis. I: Reported RLT pathways ofte...
Scheme 3: The incorporation of RLT catalysis in ATRA photocatalysis. I: The reported method is compatible wit...
Scheme 4: Pioneering and recent work on decarboxylative functionalization involving a posited RLT pathway. I:...
Scheme 5: Our lab reported decarboxylative azidation of aliphatic and benzylic acids. I: The reaction proceed...
Synthetic reactions driven by electron-donor–acceptor (EDA) complexes
- Zhonglie Yang,
- Yutong Liu,
- Kun Cao,
- Xiaobin Zhang,
- Hezhong Jiang and
- Jiahong Li
Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67
- trifluoromethylated product 126 (Scheme 44). As a rare example of EDA photochemistry in the catalytic system, only a catalytic equivalent of the electron donor was employed in this approach. Further experiments showed that the addition of inorganic salts, calcium chloride and lithium chloride, could increase the
Graphical Abstract
Scheme 1: The electron transfer process in EDA complexes.
Scheme 2: Synthesis of benzo[b]phosphorus oxide 3 initiated by an EDA complex.
Scheme 3: Mechanism of the synthesis of quinoxaline derivative 7.
Scheme 4: Synthesis of imidazole derivative 10 initiated by an EDA complex.
Scheme 5: Synthesis of sulfamoylation product 12 initiated by an EDA complex.
Scheme 6: Mechanism of the synthesis of sulfamoylation product 12.
Scheme 7: Synthesis of indole derivative 22 initiated by an EDA complex.
Scheme 8: Synthesis of perfluoroalkylated pyrimidines 26 initiated by an EDA complex.
Scheme 9: Synthesis of phenanthridine derivative 29 initiated by an EDA complex.
Scheme 10: Synthesis of cis-tetrahydroquinoline derivative 32 initiated by an EDA complex.
Scheme 11: Mechanism of the synthesis of cis-tetrahydroquinoline derivative 32.
Scheme 12: Synthesis of phenanthridine derivative 38 initiated by an EDA complex.
Scheme 13: Synthesis of spiropyrroline derivative 40 initiated by an EDA complex.
Scheme 14: Synthesis of benzothiazole derivative 43 initiated by an EDA complex.
Scheme 15: Synthesis of perfluoroalkyl-s-triazine derivative 45 initiated by an EDA complex.
Scheme 16: Synthesis of indoline derivative 47 initiated by an EDA complex.
Scheme 17: Mechanism of the synthesis of spirocyclic indoline derivative 47.
Scheme 18: Synthesis of cyclobutane product 50 initiated by an EDA complex.
Scheme 19: Mechanism of the synthesis of spirocyclic indoline derivative 50.
Scheme 20: Synthesis of 1,3-oxazolidine compound 59 initiated by an EDA complex.
Scheme 21: Synthesis of trifluoromethylated product 61 initiated by an EDA complex.
Scheme 22: Synthesis of indole alkylation product 64 initiated by an EDA complex.
Scheme 23: Synthesis of perfluoroalkylation product 67 initiated by an EDA complex.
Scheme 24: Synthesis of hydrotrifluoromethylated product 70 initiated by an EDA complex.
Scheme 25: Synthesis of β-trifluoromethylated alkyne product 71 initiated by an EDA complex.
Scheme 26: Mechanism of the synthesis of 2-phenylthiophene derivative 74.
Scheme 27: Synthesis of allylated product 80 initiated by an EDA complex.
Scheme 28: Synthesis of trifluoromethyl-substituted alkynyl product 84 initiated by an EDA complex.
Scheme 29: Synthesis of dearomatized fluoroalkylation product 86 initiated by an EDA complex.
Scheme 30: Mechanism of the synthesis of dearomatized fluoroalkylation product 86.
Scheme 31: Synthesis of C(sp3)–H allylation product 91 initiated by an EDA complex.
Scheme 32: Synthesis of perfluoroalkylation product 93 initiated by an EDA complex.
Scheme 33: Synthesis of spirocyclic indolene derivative 95 initiated by an EDA complex.
Scheme 34: Synthesis of perfluoroalkylation product 97 initiated by an EDA complex.
Scheme 35: Synthesis of alkylated indole derivative 100 initiated by an EDA complex.
Scheme 36: Mechanism of the synthesis of alkylated indole derivative 100.
Scheme 37: Synthesis of arylated oxidized indole derivative 108 initiated by an EDA complex.
Scheme 38: Synthesis of 4-ketoaldehyde derivative 111 initiated by an EDA complex.
Scheme 39: Mechanism of the synthesis of 4-ketoaldehyde derivative 111.
Scheme 40: Synthesis of perfluoroalkylated olefin 118 initiated by an EDA complex.
Scheme 41: Synthesis of alkylation product 121 initiated by an EDA complex.
Scheme 42: Synthesis of acylation product 123 initiated by an EDA complex.
Scheme 43: Mechanism of the synthesis of acylation product 123.
Scheme 44: Synthesis of trifluoromethylation product 126 initiated by an EDA complex.
Scheme 45: Synthesis of unnatural α-amino acid 129 initiated by an EDA complex.
Scheme 46: Synthesis of thioether derivative 132 initiated by an EDA complex.
Scheme 47: Synthesis of S-aryl dithiocarbamate product 135 initiated by an EDA complex.
Scheme 48: Mechanism of the synthesis of S-aryl dithiocarbamate product 135.
Scheme 49: Synthesis of thioether product 141 initiated by an EDA complex.
Scheme 50: Mechanism of the synthesis of borate product 144.
Scheme 51: Synthesis of boronation product 148 initiated by an EDA complex.
Scheme 52: Synthesis of boration product 151 initiated by an EDA complex.
Scheme 53: Synthesis of boronic acid ester derivative 154 initiated by an EDA complex.
Scheme 54: Synthesis of β-azide product 157 initiated by an EDA complex.
Scheme 55: Decarboxylation reaction initiated by an EDA complex.
Scheme 56: Synthesis of amidated product 162 initiated by an EDA complex.
Scheme 57: Synthesis of diethyl phenylphosphonate 165 initiated by an EDA complex.
Scheme 58: Mechanism of the synthesis of diethyl phenylphosphonate derivative 165.
Scheme 59: Synthesis of (Z)-2-iodovinyl phenyl ether 168 initiated by an EDA complex.
Scheme 60: Mechanism of the synthesis of (Z)-2-iodovinyl phenyl ether derivative 168.
Scheme 61: Dehalogenation reaction initiated by an EDA complex.
Syntheses of spliceostatins and thailanstatins: a review
- William A. Donaldson
Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166
- -butyl esters with formic acid gave the carboxylic acid 9, 7, or 5. Additionally, the treatment of the thailanstatin A tert-butyl ester with lithium chloride generated the thailanstatin B tert-butyl ester. Ghosh used a similar cross-metathesis/Suzuki–Miyaura coupling sequence for the preparation of
Graphical Abstract
Figure 1: Structures of spliceostatins/thailanstatins.
Scheme 1: Synthetic routes to protected (2Z,4S)-4-hydroxy-2-butenoic acid fragments.
Scheme 2: Kitahara synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 3: Koide synthesis of (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 4: Nicolaou synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 5: Jacobsen synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 6: Unproductive attempt to generate the (all-cis)-tetrahydropyranone 50.
Scheme 7: Ghosh synthesis of the C-7–C-14 (all-cis)-tetrahydropyran segment.
Scheme 8: Ghosh’s alternative route to the (all-cis)-tetrahydropyranone 50.
Scheme 9: Alternative synthesis of the dihydro-3-pyrone 58.
Scheme 10: Kitahara’s 1st-generation synthesis of the C-1–C-6 fragment of FR901464 (1).
Scheme 11: Kitahara 1st-generation synthesis of the C-1–C-6 fragment of FR901464 (1).
Scheme 12: Nimura/Arisawa synthesis of the C-1-phenyl segment.
Scheme 13: Ghosh synthesis of the C-1–C-6 fragment of FR901464 (1) from (R)-glyceraldehyde acetonide.
Scheme 14: Jacobsen synthesis of the C-1–C-7 segment of FR901464 (1).
Scheme 15: Koide synthesis of the C-1–C-7 segment of FR901464 (1).
Scheme 16: Ghosh synthesis of the C-1–C-5 segment 102 of thailanstatin A (7).
Scheme 17: Nicolaou synthesis of the C-1–C-9 segments of spliceostatin D (9) and thailanstatins A (7) and B (5...
Scheme 18: Ghosh synthesis of the C-1–C-6 segment 115 of spliceostatin E (10).
Scheme 19: Fragment coupling via Wittig and modified Julia olefinations by Kitahara.
Scheme 20: Fragment coupling via cross-metathesis by Koide.
Scheme 21: The Ghosh synthesis of spliceostatin A (4), FR901464 (1), spliceostatin E (10), and thailanstatin m...
Scheme 22: Arisawa synthesis of a C-1-phenyl analog of FR901464 (1).
Scheme 23: Jacobsen fragment coupling by a Pd-catalyzed Negishi coupling.
Scheme 24: Nicolaou syntheses of thailanstatin A and B (7 and 5) and spliceostatin D (9) via a Pd-catalyzed Su...
Scheme 25: The Ghosh synthesis of spliceostatin G (11) via Suzuki–Miyaura coupling.
Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides
- Mateo Berton,
- Kevin Sheehan,
- Andrea Adamo and
- D. Tyler McQuade
Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115
- batch-to-batch variability. Tubular reactors of solid reagents combined with solution-phase reagents enable the continuous-flow preparation of organomagnesium reagents. The use of stratified packed-bed columns of magnesium metal and lithium chloride for the synthesis of highly concentrated turbo
- fresh organomagnesium reagents on a discovery scale and will do so independent from the operator’s experience in flow and/or organometallic chemistry. Keywords: Knochel–Hauser base; lithium chloride; magnesium; on-demand; packed-bed reactors; plug and flow reactor; synthesizer; turbo Grignard reagent
- chloride–lithium chloride complex (iPrMgCl⋅LiCl), known as turbo Grignard [45]. In addition to being widely cited, turbo Grignard is a popular discovery-scale tool in the pharmaceutical industry [32] and has shown an excellent selectivity on a large scale [46]. Halomagnesium amide LiCl adducts, e.g., the
Graphical Abstract
Figure 1: Comparing on-demand coffee and turbo Grignard pod-style machines.
Figure 2: Ranking of the 20 most cited Grignard reagents (SciFinder March 26, 2019).
Figure 3: On-demand prototype. A) Inside view of the pump with a flexible bag containing a yellow liquid layi...
Figure 4: Temperature evolution measured with thermocouples along the column outer surface at three different...
Figure 5: Stratified bicomponent column (Diba Omnifit EZ Solvent Plus) composed of magnesium (chips/powder, 1...
Scheme 1: Continuous flow synthesis of TMPMgCl⋅LiCl with a stratified packed-bed column of activated magnesiu...
Scheme 2: Continuous flow synthesis of TMPMgCl⋅LiBr with a stratified packed-bed column of activated magnesiu...
Scheme 3: Continuous flow synthesis of t-AmylOMgCl⋅LiCl with a stratified packed-bed column of activated magn...
Figure 6: Steady-state concentration stability during the conversion of iPrCl in THF (56 mL, 2.2 M) into iPrM...
Scheme 4: Synthesis of iPrMgCl⋅LiCl on the ODR prototype.
Scheme 5: Synthesis of HMDSMgCl⋅LiCl on the ODR prototype.
Architecture and synthesis of P,N-heterocyclic phosphine ligands
- Wisdom A. Munzeiwa,
- Bernard Omondi and
- Vincent O. Nyamori
Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35
- deprotection then furnished 83b in reasonable yields between 68 and 87%. Bis(diphenylphosphine)-substituted imidazoles were also synthesized by Karthik et al. [87] starting from the diiodoimidazole derivative 84. The lithium chloride mediated magnesium/iodine exchange reaction of 84 followed by the addition of
Graphical Abstract
Scheme 1: Synthesis of pyridylphosphine ligands.
Figure 1: Pyridylphosphine ligands.
Scheme 2: Synthesis of piperidyl- and oxazinylphosphine ligands.
Scheme 3: Synthesis of linear multi-chelate pyridylphosphine ligands.
Scheme 4: Synthesis of chiral acetal pyridylphosphine ligands.
Scheme 5: Synthesis of diphenylphosphine-substituted triazine ligands.
Scheme 6: Synthesis of (pyridine-2-ylmethyl)phosphine ligands.
Scheme 7: Synthesis of diphosphine pyrrole ligands.
Scheme 8: Synthesis of 4,5-diazafluorenylphosphine ligands.
Scheme 9: Synthesis of thioether-containing pyridyldiphosphine ligands starting from ethylene sulfide and dip...
Scheme 10: Synthesis of monoterpene-derived phosphine pyridine ligands.
Scheme 11: Synthesis of N-phenylphosphine-substituted imidazole ligands.
Scheme 12: Synthesis of triazol-4-ylphosphine ligands.
Scheme 13: Synthesis of phosphanyltriazolopyridines and product selectivity depending on the substituents’ eff...
Scheme 14: Synthesis of PTA-phosphine ligands.
Scheme 15: Synthesis of isomeric phosphine dipyrazole ligands by varying the reaction temperature.
Scheme 16: Synthesis of N-tethered phosphine imidazolium ligands (route A) and diphosphine imidazolium ligands...
Scheme 17: Synthesis of {1-[2-(pyridin-2-yl)- (R = CH) and {1-[2-(pyrazin-2-yl)quinazolin-4-yl]naphthalen-2-yl...
Scheme 18: Synthesis of oxazolylindolylphosphine ligands 102.
Scheme 19: Synthesis of pyrrolylphosphine ligands.
Scheme 20: Synthesis of phosphine guanidinium ligands.
Scheme 21: Synthesis of a polydentate aminophosphine ligand.
Scheme 22: Synthesis of quinolylphosphine ligands.
Scheme 23: Synthesis of N-(triazolylmethyl)phosphanamine ligands.
Figure 2: Triazolylphosphanamine ligands synthesized by Wassenaar’s method [22].
Scheme 24: Synthesis of oxazaphosphorines.
Scheme 25: Synthesis of paracyclophane pyridylphosphine ligands.
Scheme 26: Synthesis of triazolylphosphine ligands.
Figure 3: Click-phosphine ligands.
Scheme 27: Ferrocenyl pyridylphosphine imine ligands.
Scheme 28: Synthesis of phosphinooxazolines (PHOX).
Scheme 29: Synthesis of ferrocenylphosphine oxazoles.
Efficient synthesis of 4-substituted-ortho-phthalaldehyde analogues: toward the emergence of new building blocks
- Clémence Moitessier,
- Ahmad Rifai,
- Pierre-Edouard Danjou,
- Isabelle Mallard and
- Francine Cazier-Dennin
Beilstein J. Org. Chem. 2019, 15, 721–726, doi:10.3762/bjoc.15.67
- deprotection agent was tested, trimethylsilyl iodide, as it was recently published by Danjou et al. [24] as a removal agent of methoxy groups on calixarenes architectures. Although we succeeded with the removal of methoxy groups, both aldehydes were reduced. Furthermore, the lithium chloride/N,N
- -dimethylformamide system was tested according to the study of Fang et al. [25] revealing that the methoxy group in the meta-position of an electron-withdrawing substituents can be removed under microwave irradiation. However, when testing the system on 5b, no reaction occurred. Another experiment with lithium
- chloride/N,N-dimethylformamide in the presence of a catalytic amount of p-toluenesulfonic acid ended up with only the formation of OPA. Regeneration of phenols from methyl ethers have also been tested by Boovanahalli et al. [26] by using an ionic liquid such as 1-butyl-3-methylimidazolium bromide ([Bmim]Br
Graphical Abstract
Scheme 1: Synthesis of 4,5-dihydroisobenzofuran-5-ol (3).
Scheme 2: Protection strategy of 4,5-dihydroisobenzofuran-5-ol (3).
Scheme 3: Oxidation of 5-substituted-4,5-dihydroisobenzofuran-5-ol in presence of SeO2 or DDQ.
Scheme 4: Synthesis of 4-hydroxy-ortho-phthalaldehyde (6) through MAOS demethylation of 4-methoxy-ortho-phtha...
Quinolines from the cyclocondensation of isatoic anhydride with ethyl acetoacetate: preparation of ethyl 4-hydroxy-2-methylquinoline-3-carboxylate and derivatives
- Nicholas G. Jentsch,
- Jared D. Hume,
- Emily B. Crull,
- Samer M. Beauti,
- Amy H. Pham,
- Julie A. Pigza,
- Jacques J. Kessl and
- Matthew G. Donahue
Beilstein J. Org. Chem. 2018, 14, 2529–2536, doi:10.3762/bjoc.14.229
- heterocycle at position 4 is installed by Suzuki coupling with iodide 3a that is synthesized in three steps from ethyl aryl oxalate 4a. The α-ketoester side chain at position 3 was installed by selective halogen-metal exchange of iodide 5a with isopropylmagnesium chloride lithium chloride complex followed by
- tartrate. Subsequent oxidation of the primary alcohol to the aldehyde 15 was accomplished with the pyridine sulfur trioxide complex in 52% yield over two-steps [29]. The carbon atom at the acid oxidation state was installed by addition of trimethylsilyl cyanide to the aldehyde 15 in the presence of lithium
- chloride in THF [30]. Initially, the trimethylsilyl cyanohydrin 16 was subjected to solvolysis in ethanol with aqueous sulfuric acid. Unfortunately, those conditions resulted in displacement of the 4-chloro substituent with ethanol giving the 4-ethyl ether 17 in 35% yield. To circumvent this undesired
Graphical Abstract
Figure 1: Investigational non-catalytic HIV-1 Integrase inhibitors.
Scheme 1: Boehringer Ingelheim retrosynthesis of quinoline 1.
Scheme 2: Quinoline ring condensation strategies.
Scheme 3: Isatoic anhydrides from anthranilic acids with triphosgene.
Scheme 4: Substituted 2-methyl-4-hydroxyquinolines from isatoic anhydrides and ethyl acetoacetate.
Scheme 5: Mechanistic hypothesis for the cyclocondensation reaction.
Scheme 6: Quinoline synthesis with ethyl acetylpyruvate.
Scheme 7: Elaboration of the benzoic acid ethyl ester to the acetic acid residue.
Scheme 8: Umpolung addition of ethoxycarbonyl via a MAC strategy.
Mild and selective reduction of aldehydes utilising sodium dithionite under flow conditions
- Nicole C. Neyt and
- Darren L. Riley
Beilstein J. Org. Chem. 2018, 14, 1529–1536, doi:10.3762/bjoc.14.129
- reduction utilizing solid mixes of sodium borohydride, lithium chloride and celite [12], and the Ley group were able to demonstrate a green transfer hydrogenation of ketones under flow using catalytic lithium tert-butoxide in isopropanol [13]. We recently published a batch–flow hybrid synthesis of the
Graphical Abstract
Scheme 1: Sodium dithionite-mediated reductions under basic conditions.
Figure 1: Uniqsis FlowSyn Stainless Steel Flow reactor.
Figure 2: Flow reactor configuration for the reduction of aldehydes and ketones.
Figure 3: NMR spectra showing the optimisation of the dithionite reduction for the reduction of benzaldehyde.
Figure 4: Selective reduction of an aldehyde in the presence of a ketone.
Figure 5: Flow reactor set-up for the continuous reduction of aldehydes.
One hundred years of benzotropone chemistry
- Arif Dastan,
- Haydar Kilic and
- Nurullah Saracoglu
Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98
- (Scheme 8). After bromination of 40 with molecular bromine in carbon tetrachloride, direct dehydrobromination with lithium chloride in dimethylformamide gave 11 in 85% isolated yield. Müller’s group reported an alternative synthesis for 11 starting from the carbene adduct 41 over two or three steps [55
- bromination of Julia’s ketone 163 followed by spontaneous elimination of hydrogen bromide at the temperature of the reaction. 2,3-Benzotropone (12) was also prepared by bromination of 1-benzosuberone (162) using both NBS and molecular bromine followed by dehydrobromination (using lithium chloride in
- prepared by reacting α-tetralone (171) with ethyl orthoformate in the presence of an acid catalyst. Subsequent successive reactions are dihalocarbene addition to enolether 172, ring expansion of the adduct 173 to halocycloheptadienone 168, and dehydrohalogenation of 168 with lithium chloride. Later
Graphical Abstract
Scheme 1: Tropone (1), tropolone (2) and their resonance structures.
Figure 1: Natural products containing a tropone nucleus.
Figure 2: Possible isomers 11–13 of benzotropone.
Scheme 2: Synthesis of benzotropones 11 and 12.
Scheme 3: Oxidation products of benzotropylium fluoroborate (16).
Scheme 4: Oxidation of 7-bromo-5H-benzo[7]annulene (22).
Scheme 5: Synthesis of 4,5-benzotropone (11) using o-phthalaldehyde (27).
Scheme 6: Synthesis of 4,5-benzotropone (11) starting from oxobenzonorbornadiene 31.
Scheme 7: Acid-catalyzed cleavage of oxo-bridge of 34.
Scheme 8: Synthesis of 4,5-benzotropone (11) from o-xylylene dibromide (38).
Scheme 9: Synthesis of 4,5-benzotropone (11) via the carbene adduct 41.
Scheme 10: Heck coupling strategy for the synthesis of 11.
Scheme 11: Synthesis of benzofulvalenes via carbonyl group of 4,5-benzotropone (11).
Figure 3: Some cycloheptatrienylium cations.
Scheme 12: Synthesis of condensation product 63 and its subsequent oxidative cyclization products.
Figure 4: A novel series of benzo[7]annulenes prepared from 4,5-benzotropone (11).
Scheme 13: Preparation of substituted benzo[7]annulene 72 using the Mukaiyama-Michael reaction.
Figure 5: Possible benzo[7]annulenylidenes 73–75.
Scheme 14: Thermal and photochemical decomposition of 7-diazo-7H-benzo[7]annulene (76) and the trapping of int...
Scheme 15: Synthesis of benzoheptafulvalene 86.
Scheme 16: Synthesis of 7-(diphenylmethylene)-7H-benzo[7]annulene (89).
Scheme 17: Reaction of 4,5-benzotropone (11) with dimethyl diazomethane.
Scheme 18: Synthesis of dihydrobenzomethoxyazocine 103.
Scheme 19: Synthesis and reducibility of benzo-homo-2-methoxyazocines.
Scheme 20: Synthesis of 4,5-benzohomotropones 104 and 115 from 4,5-benzotropones 11 and 113.
Scheme 21: A catalytic deuterogenation of 4,5-benzotropone (11) and synthesis of 5-monosubstituted benzo[7]ann...
Scheme 22: Synthesis of methyl benzo[7]annulenes 131 and 132.
Scheme 23: Ambident reactivity of halobenzo[7]annulenylium cations 133a/b.
Scheme 24: Preparation of benzo[7]annulenylidene–iron complexes 147.
Scheme 25: Synthesis of 1-ethynylbenzotropone (150) and the etheric compound 152 from 4,5-benzotropone (11) wi...
Scheme 26: Thermal decomposition of 4,5-benzotropone (11).
Scheme 27: Reaction of 4,5-benzotropone (11) with 1,2-ethanediol and 1,2-ethanedithiol.
Scheme 28: Conversions of 1-benzosuberone (162) to 2,3-benzotropone (12).
Scheme 29: Synthesis strategies for 2,3-bezotropone (12) using 1-benzosuberones.
Scheme 30: Oxidation-based synthesis of 2,3-benzotropone (12) via 1-benzosuberone (162).
Scheme 31: Synthesis of 2,3-benzotropone (12) from α-tetralone (171) via ring-expansion.
Scheme 32: Preparation of 2,3-benzotropone (12) by using of benzotropolone 174.
Figure 6: Benzoheptafulvenes as condensation products of 2,3-benzotropone (12).
Scheme 33: Conversion of 2,3-benzotropone (12) to tosylhydrazone salt 182 and gem-dichloride 187.
Figure 7: Benzohomoazocines 191–193 and benzoazocines 194–197.
Scheme 34: From 2,3-benzotropone (12) to carbonium ions 198–201.
Scheme 35: Cycloaddition reactions of 2,3-benzotropone (12).
Scheme 36: Reaction of 2,3-benzotropone (12) with various reagents and compounds.
Figure 8: 3,4-Benzotropone (13) and its resonance structure.
Scheme 37: Synthesis of 6,7-benzobicyclo[3.2.0]hepta-3,6-dien-2-one (230).
Figure 9: Photolysis and thermolysis products of 230.
Figure 10: Benzotropolones and their tautomeric structures.
Scheme 38: Synthesis strategies of 4,5-benzotropolone (238).
Scheme 39: Synthesis protocol for 2-hydroxy-4,5-benzotropone (238) using oxazole-benzo[7]annulene 247.
Figure 11: Some quinoxaline and pyrazine derivatives 254–256 prepared from 4,5-benzotropolone (238).
Scheme 40: Nitration product of 4,5-benzotropolone (238) and its isomerization to 1-nitro-naphthoic acid (259)....
Scheme 41: Synthesis protocol for 6-hydroxy-2,3-benzotropone (239) from benzosuberone (162).
Scheme 42: Various reactions via 6-hydroxy-2,3-benzotropone (239).
Scheme 43: Photoreaction of 6-hydroxy-2,3-benzotropone (239).
Scheme 44: Synthesis of 7-hydroxy-2,3-benzotropone (241) from benzosuberone (162).
Scheme 45: Synthesis strategy for 7-hydroxy-2,3-benzotropone (241) from ketone 276.
Scheme 46: Synthesis of 7-hydroxy-2,3-benzotropone (241) from β-naphthoquinone (280).
Scheme 47: Synthesis of 7-hydroxy-2,3-benzotropone (241) from bicyclic endoperoxide 213.
Scheme 48: Synthesis of 7-hydroxy-2,3-benzotropone (241) by ring-closing metathesis.
Figure 12: Various monosubstitution products 289–291 of 7-hydroxy-2,3-benzotropone (241).
Scheme 49: Reaction of 7-hydroxy-2,3-benzotropone (241) with various reagents.
Scheme 50: Synthesis of 4-hydroxy-2,3-benzotropones 174 and 304 from diketones 300/301.
Scheme 51: Catalytic hydrogenation of diketones 300 and 174.
Scheme 52: Synthesis of halo-benzotropones from alkoxy-naphthalenes 306, 307 and 310.
Figure 13: Unexpected byproducts 313–315 during synthesis of chlorobenzotropone 309.
Figure 14: Some halobenzotropones and their cycloadducts.
Scheme 53: Multisep synthesis of 2-chlorobenzotropone 309.
Scheme 54: A multistep synthesis of 2-bromo-benzotropone 26.
Scheme 55: A multistep synthesis of bromo-2,3-benzotropones 311 and 316.
Scheme 56: Oxidation reactions of 8-bromo-5H-benzo[7]annulene (329) with some oxidants.
Scheme 57: Synthesis of 2-bromo-4,5-benzotropone (26).
Scheme 58: Synthesis of 6-chloro-2,3-benzotropone (335) using LiCl and proposed intermediate 336.
Scheme 59: Reaction of 7-bromo-2,3-benzotropone (316) with methylamine.
Scheme 60: Reactions of bromo-2,3-benzotropones 26 and 311 with dimethylamine.
Scheme 61: Reactions of bromobenzotropones 311 and 26 with NaOMe.
Scheme 62: Reactions of bromobenzotropones 26 and 312 with t-BuOK in the presence of DPIBF.
Scheme 63: Cobalt-catalyzed reductive cross-couplings of 7-bromo-2,3-benzotropone (316) with cyclic α-bromo en...
Figure 15: Cycloadduct 357 and its di-π-methane rearrangement product 358.
Scheme 64: Catalytic hydrogenation of 2-chloro-4,5-benzotropone (311).
Scheme 65: Synthesis of dibromo-benzotropones from benzotropones.
Scheme 66: Bromination/dehydrobromination of benzosuberone (162).
Scheme 67: Some transformations of isomeric dibromo-benzotropones 261A/B.
Scheme 68: Transformations of benzotropolone 239B to halobenzotropolones 369–371.
Figure 16: Bromobenzotropolones 372–376 and 290 prepared via bromination/dehydrobromination strategy.
Scheme 69: Synthesis of some halobenzotropolones 289, 377 and 378.
Figure 17: Bromo-chloro-derivatives 379–381 prepared via chlorination.
Scheme 70: Synthesis of 7-iodo-3,4-benzotropolone (382).
Scheme 71: Hydrogenation of bromobenzotropolones 369 and 370.
Scheme 72: Debromination reactions of mono- and dibromides 290 and 375.
Figure 18: Nitratation and oxidation products of some halobenzotropolenes.
Scheme 73: Azo-coupling reactions of some halobenzotropolones 294, 375 and 378.
Figure 19: Four possible isomers of dibenzotropones 396–399.
Figure 20: Resonance structures of tribenzotropone (400).
Scheme 74: Two synthetic pathways for tribenzotropone (400).
Scheme 75: Synthesis of tribenzotropone (400) from dibenzotropone 399.
Scheme 76: Synthesis of tribenzotropone (400) from 9,10-phenanthraquinone (406).
Scheme 77: Synthesis of tribenzotropone (400) from trifluoromethyl-substituted arene 411.
Figure 21: Dibenzosuberone (414).
Figure 22: Reduction products 415 and 416 of tribenzotropone (400).
Figure 23: Structures of tribenzotropone dimethyl ketal 417 and 4-phenylfluorenone (412) and proposed intermed...
Figure 24: Structures of benzylidene- and methylene-9H-tribenzo[a,c,e][7]annulenes 419 and 420 and chiral phos...
Figure 25: Structures of tetracyclic alcohol 422, p-quinone methide 423 and cation 424.
Figure 26: Structures of host molecules 425–427.
Scheme 78: Synthesis of non-helical overcrowded derivatives syn/anti-431.
Figure 27: Hexabenzooctalene 432.
Figure 28: Structures of possible eight isomers 433–440 of naphthotropone.
Scheme 79: Synthesis of naphthotropone 437 starting from 1-phenylcycloheptene (441).
Scheme 80: Synthesis of 10-hydroxy-11H-cyclohepta[a]naphthalen-11-one (448) from diester 445.
Scheme 81: Synthesis of naphthotropone 433.
Scheme 82: Synthesis of naphthotropones 433 and 434 via cycloaddition reaction.
Scheme 83: Synthesis of naphthotropone 434 starting from 452.
Figure 29: Structures of tricarbonyl(tropone)irons 458, and possible cycloadducts 459.
Scheme 84: Synthesis of naphthotropone 436.
Scheme 85: Synthesis of precursor 465 for naphthotropone 435.
Scheme 86: Generation of naphthotropone 435 from 465.
Figure 30: Structures of tropylium cations 469 and 470.
Figure 31: Structures of tropylium ions 471+.BF4−, 472+.BF4−, and 473+.BF4−.
Scheme 87: Synthesis of tropylium ions 471+.BF4− and 479+.ClO4−.
Scheme 88: Synthesis of 1- and 2-methylanthracene (481 and 482) via carbene–carbene rearrangement.
Figure 32: Trapping products 488–490.
Scheme 89: Generation and chemistry of a naphthoannelated cycloheptatrienylidene-cycloheptatetraene intermedia...
Scheme 90: Proposed intermediates and reaction pathways for adduct 498.
Scheme 91: Exited-state intramolecular proton transfer of 505.
Figure 33: Benzoditropones 506 and 507.
Scheme 92: Synthesis of benzoditropone 506e.
Scheme 93: Synthetic approaches for dibenzotropone 507 via tropone (1).
Scheme 94: Formation mechanisms of benzoditropone 507 and 516 via 515.
Scheme 95: Synthesis of benzoditropones 525 and 526 from pyromellitic dianhydride (527).
Figure 34: Possible three benzocyclobutatropones 534–536.
Scheme 96: Synthesis of benzocyclobutatropones 534 and 539.
Scheme 97: Synthesis attempts for benzocyclobutatropone 545.
Scheme 98: Generation and trapping of symmetric benzocyclobutatropone 536.
Scheme 99: Synthesis of chloro-benzocyclobutatropone 552 and proposed mechanism of fluorenone derivatives.
Scheme 100: Synthesis of tropolone analogue 559.
Scheme 101: Synthesis of tropolones 561 and 562.
Figure 35: o/p-Tropoquinone rings (563 and 564) and benzotropoquinones (565–567).
Scheme 102: Synthesis of benzotropoquinone 566.
Scheme 103: Synthesis of benzotropoquinone 567 via a Diels–Alder reaction.
Figure 36: Products 575–577 through 1,2,3-benzotropoquinone hydrate 569.
Scheme 104: Structures 578–582 prepared from tropoquinone 567.
Figure 37: Two possible structures 583 and 584 for dibenzotropoquinone, and precursor compound 585 for 583.
Scheme 105: Synthesis of saddle-shaped ketone 592 using dibenzotropoquinone 584.
Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions
- Michal Medvecký,
- Igor Linder,
- Luise Schefzig,
- Hans-Ulrich Reissig and
- Reinhold Zimmer
Beilstein J. Org. Chem. 2016, 12, 2898–2905, doi:10.3762/bjoc.12.289
- lithium chloride [35] leading to the expected coupling products syn-13 and syn-14 in 39% and 82% yield, respectively (Scheme 5). In both cases, only the E-configured 2-substituted alkyl acrylates were isolated. The moderate yield in the Heck reaction with methyl acrylate 12a is very likely caused by the
Graphical Abstract
Scheme 1: Access to enantiopure 3,6-dihydro-1,2-oxazines 3 via lithiated alkoxyallenes 1 and carbohydrate-der...
Scheme 2: Iodination of 1,2-oxazines syn-3a–c and anti-3a,d leading to 5-iodo-substituted 1,2-oxazines syn-4a...
Scheme 3: Sonogashira reactions of 4-methoxy-1,2-oxazines syn-4a, anti-4a and anti-4d leading to 5-alkynyl-su...
Scheme 4: Sonogashira reactions of D-glyceraldehyde-derived 1,2-oxazines syn-4a–c leading to 5-alkynyl-substi...
Scheme 5: Heck reactions of 1,2-oxazine syn-4a leading to 5-alkenyl-substituted 1,2-oxazines syn-13, syn-14 a...
Scheme 6: Suzuki–Miyaura reactions of 1,2-oxazines syn-4a, syn-4b and anti-4d leading to 5-styryl-substituted...
Scheme 7: Cross-coupling reaction of 1,2-oxazine anti-4d leading to 5-cyano-substituted 1,2-oxazine anti-25.
Scheme 8: Desilylation of 1,2-oxazine syn-5 and subsequent click reaction with benzyl azide leading to 5-(1,2...
Scheme 9: Hydrogenation of 1,2-oxazine syn-21 leading to γ-amino alcohols 27a,b and subsequent ring closure t...
Scheme 10: Hydrogenation of 1,2-oxazine anti-24 to products anti-29 and anti-30.
Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties
- Pierre Boufflet,
- Sebastian Wood,
- Jessica Wade,
- Zhuping Fei,
- Ji-Seon Kim and
- Martin Heeney
Beilstein J. Org. Chem. 2016, 12, 2150–2163, doi:10.3762/bjoc.12.205
- at every 10 °C interval in order to measure spectra. Typical procedure for the synthesis of Grignard monomer To a solution of 2,5-dibromo-3-octylthiophene (361.2 mg, 1.02 mmol) in dry THF (2.86 mL) at room temperature was added isopropylmagnesium chloride lithium chloride complex (0.78 mL, 1.3 M in
Graphical Abstract
Scheme 1: Grignard metathesis polymerization method of synthesizing the diblock copolymer. Relative block len...
Figure 1: Differential scanning calorimetry thermogram (second cycle, 10 K/min) of P3OT-b-F-P3OT 2:1 before (...
Figure 2: Selected region of the 1H NMR (d2-TCE at 403 K) of P3OT-b-F-P3OT produced with 3:1 (a) and 1:3 (b) ...
Figure 3: Thin film UV–visible absorption spectra of 2:1 (a) and 1:4 (b) P3OT-b-F-P3OT polymers (red line), o...
Figure 4: Overlay of thin film UV–visible absorption spectra (a) of the two block copolymers and the correspo...
Figure 5: Thin-film UV–visible absorption spectra of a) P3OT, b) F-P3OT, c) P3OT-b-F-P3OT 2:1, d) P3OT-b-F-P3...
Figure 6: Temperature dependent Raman spectra measured during heating showing the main C–C and C=C stretches ...
Figure 7: Influence of temperature on the relative Raman scattering intensities of the P3OT (1446 cm−1) and F...
Reactivity studies of pincer bis-protic N-heterocyclic carbene complexes of platinum and palladium under basic conditions
- David C. Marelius,
- Curtis E. Moore,
- Arnold L. Rheingold and
- Douglas B. Grotjahn
Beilstein J. Org. Chem. 2016, 12, 1334–1339, doi:10.3762/bjoc.12.126
- .12.126 Abstract Bis-protic N-heterocyclic carbene complexes of platinum and palladium (4) yield dimeric structures 6 when treated with sodium tert-butoxide in CH2Cl2. The use of a more polar solvent (THF) and a strong base (LiN(iPr)2) gave the lithium chloride adducts monobasic complex 7 or analogous
- , Figure 2), a situation that would not be possible for a monomeric structure. Attempts to synthesize 5 using sodium alkoxide bases led to the formation of dimer structures 6 with presumed loss of NaCl. Therefore, lithium chloride adducts 7 were targeted because LiCl adduct 3 was isolable yet highly
- insight (Table 2), as exemplified by 1–3 [10]. The Δx (difference in 15N shifts for compound x) is near zero for a PNHC (1), maximum for the imidazolyl conjugate base 2, and slightly less for an imidazolyl lithium chloride adduct 3. The δN for the aprotic nitrogen incapable of acid base chemistry (N2
Graphical Abstract
Figure 1: Previously reported PNHC complexes of interest for this work, along with the targeted complex 5.
Figure 2: Crystal structure of 6-Pd. The atoms of the tert-butyl groups, C–H bonds, and the solvent have been...
Scheme 1: Formation of dimers 6-Pd and 6-Pt by addition of NaOt-Bu.
Scheme 2: Formation of 7 and 8 by addition of LiN(iPr)2 (1 or 2 equiv) (R = tert-butyl).
A modular approach to neutral P,N-ligands: synthesis and coordination chemistry
- Vladislav Vasilenko,
- Torsten Roth,
- Clemens K. Blasius,
- Sebastian N. Intorp,
- Hubert Wadepohl and
- Lutz H. Gade
Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83
- throughout the reaction, the resulting mixtures do not require a purification step beyond a filtration from toluene or hexane to remove residual lithium chloride. As has been pointed out by Dyer et al. for the structurally related N-phosphanylamidines, there are several distinct conformers of ligands 2a–c
Graphical Abstract
Figure 1: P,N-ligand frameworks studied in this work.
Scheme 1: Synthesis of N-phosphanylformamidines 2 and 3. Reaction conditions: (i) t-BuLi, THF, −78 °C to rt, ...
Scheme 2: Synthesis of phosphanylformamidines 5 and 7. Reaction conditions: (i) t-BuLi, THF, −78 °C to rt, 1 ...
Scheme 3: Synthesis of complexes [2-M(cod)]X, [3-M(cod)]X, [5-M(cod)]X and [7-M(cod)]X. M = Rh, Ir; X = BF4− ...
Figure 2: Molecular structures of [2a-Rh(cod)]+ (A), [5-Ir(cod)]+ (B), and [7-Rh(cod)]+ (C,D). Anisotropic di...
Figure 3: Coordination of ligands 2a and 5 to Rh(III) and Ir(III) precursors. Yields: [2a-Cp*RhCl]BF4 = 87%, [...
Figure 4: Molecular structures of [2a-Cp*IrI]+ (left) and [5-Cp*IrI]+ (right). Anisotropic displacement ellip...
Figure 5: Formation of palladium complexes of ligands 2a, 5 and 7. (A) Formation of [2a-PdCl2] and [2a-PdCl]2...
Figure 6: Molecular structures of [2a-PdCl2] (left) and [5-Pd(2-Me-allyl)]+ (right). Anisotropic displacement...
Selected synthetic strategies to cyclophanes
- Sambasivarao Kotha,
- Mukesh E. Shirbhate and
- Gopalkrushna T. Waghule
Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142
- muscopyridine starting with methyl acetoacetate (231). They treated 231 with 5-bromo-1-pentene to generate keto ester 232 (60%). The coupling of keto ester 232 with vinyl ketone 233 under phase-transfer catalysis conditions generated the new keto ester 234 (93%), which on treatment with lithium chloride at 120
Graphical Abstract
Figure 1: General representation of cyclophanes.
Figure 2: cyclophanes one or more with heteroatom.
Figure 3: Metathesis catalysts 12–17 and C–C coupling catalyst 18.
Figure 4: Natural products containing the cyclophane skeleton.
Figure 5: Turriane family of natural products.
Scheme 1: Synthesis of [3]ferrocenophanes through Mannich reaction. Reagents and conditions: (i) excess HNMe2...
Scheme 2: Synthesis of cyclophanes through Michael addition. Reagents and conditions: (i) xylylene dibromide,...
Scheme 3: Synthesis of normuscopyridine analogue 37 through an oxymercuration–oxidation strategy. Reagents an...
Scheme 4: Synthesis of tribenzocyclotriyne 39 through Castro–Stephens coupling reaction. Reagents and conditi...
Scheme 5: Synthesis of cyclophane 43 through Glaser–Eglinton coupling. Reagents and conditions: (i) 9,10-bis(...
Scheme 6: Synthesis of the macrocyclic C-glycosyl cyclophane through Glaser coupling. Reagents and conditions...
Scheme 7: Synthesis of cyclophane-containing complex 49 through Glaser–Eglinton coupling reaction. Reagents a...
Scheme 8: Synthesis of cyclophane 53 through Glaser–Eglinton coupling. Reagents and conditions: (i) K2CO3, ac...
Figure 6: Cyclophanes 54–56 that have been synthesized through Glaser–Eglinton coupling.
Figure 7: Synthesis of tetrasubstituted [2.2]paracyclophane 57 and chiral cyclophyne 58 through Eglinton coup...
Scheme 9: Synthesis of cyclophane through Glaser–Hay coupling reaction. Reagents and conditions: (i) CuCl2 (1...
Scheme 10: Synthesis of seco-C/D ring analogs of ergot alkaloids through intramolecular Heck reaction. Reagent...
Scheme 11: Synthesis of muscopyridine 73 via Kumada coupling. Reagents and conditions: (i) 72, THF, ether, 20 ...
Scheme 12: Synthesis of the cyclophane 79 via McMurry coupling. Reagents and conditions: (i) 75, decaline, ref...
Scheme 13: Synthesis of stilbenophane 81 via McMurry coupling. Reagents and conditions: (i) TiCl4, Zn, pyridin...
Scheme 14: Synthesis of stilbenophane 85 via McMurry coupling. Reagents and conditions: (i) NBS (2 equiv), ben...
Figure 8: List of cyclophanes prepared via McMurry coupling reaction as a key step.
Scheme 15: Synthesis of paracyclophane by cross coupling involving Pd(0) catalyst. Reagents and conditions: (i...
Scheme 16: Synthesis of the cyclophane 112 via the pinacol coupling and 113 by RCM. Reagents and conditions: (...
Scheme 17: Synthesis of cyclophane derivatives 122a–c via Sonogoshira coupling. Reagents and conditions: (i) C...
Scheme 18: Synthesis of cyclophane 130 via Suzuki–Miyaura reaction as a key step. Reagents and conditions: (i)...
Scheme 19: Synthesis of the mycocyclosin via Suzuki–Miyaura cross coupling. Reagents and conditions: (i) benzy...
Scheme 20: Synthesis of cyclophanes via Wurtz coupling reaction Reagents and conditions: (i) PhLi, Et2O, C6H6,...
Scheme 21: Synthesis of non-natural glycophanes using alkyne metathesis. Reagents and conditions: (i) G-I (12)...
Figure 9: Synthesis of cyclophanes via ring-closing alkyne metathesis.
Scheme 22: Synthesis of crownophanes by cross-enyne metathesis. Reagents and conditions: (i) G-II (13), 5 mol ...
Scheme 23: Synthesis of (−)-cylindrocyclophanes A (156) and (−)-cylindrocyclophanes F (155). Reagents and cond...
Scheme 24: Synthesis of cyclophane 159 derivatives via SM cross-coupling and RCM. Reagents and conditions: (i)...
Scheme 25: Sexithiophene synthesis via cross metathesis. Reagents and conditions: (i) 161, Pd(PPh3)4, K2CO3, T...
Scheme 26: Synthesis of pyrrole-based cyclophane using enyne metathesis. Reagents and conditions: (i) Se, chlo...
Scheme 27: Synthesis of macrocyclic derivatives by RCM. Reagents and conditions: (i) G-I/G-II, CH2Cl2, 0.005 M...
Scheme 28: Synthesis of enantiopure β-lactam-based dienyl bis(dihydrofuran) 179. Reagents and conditions: (i) ...
Scheme 29: Synthesis of a [1.1.6]metaparacyclophane derivative 183 via SM cross coupling. Reagents and conditi...
Scheme 30: Synthesis of a [1.1.6]metaparacyclophane derivative 190 via SM cross coupling. Reagents and conditi...
Scheme 31: Template-promoted synthesis of cyclophanes involving RCM. Reagents and conditions: (i) acenaphthene...
Scheme 32: Synthesis of [3.4]cyclophane derivatives 200 via SM cross coupling and RCM. Reagents and conditions...
Figure 10: Examples for cyclophanes synthesized by RCM.
Scheme 33: Synthesis of the longithorone C framework assisted by fluorinated auxiliaries. Reagents and conditi...
Scheme 34: Synthesis of the longithorone framework via RCM. Reagents and conditions: (i) 213, NaH, THF, rt, 10...
Scheme 35: Synthesis of floresolide B via RCM as a key step. Reagents and conditions: (i) G-II (13, 0.1 equiv)...
Scheme 36: Synthesis of normuscopyridine (223) by the RCM strategy. Reagents and condition: (i) Mg, THF, hexen...
Scheme 37: Synthesis of muscopyridine (73) via RCM. Reagents and conditions: (i) 225, NaH, THF, 0 °C to rt, 1....
Scheme 38: Synthesis of muscopyridine (73) via RCM strategy. Reagents and conditions: (i) NaH, n-BuLi, 5-bromo...
Scheme 39: Synthesis of pyridinophane derivatives 223 and 245. Reagents and conditions: (i) PhSO2Na, TBAB, CH3...
Scheme 40: Synthesis of metacyclophane derivatives 251 and 253. Reagents and conditions: (i) 240, NaH, THF, rt...
Scheme 41: Synthesis of normuscopyridine and its higher analogues. Reagents and conditions: (i) alkenyl bromid...
Scheme 42: Synthesis of fluorinated ferrocenophane 263 via a [2 + 2] cycloaddition. Reagents and conditions: (...
Scheme 43: Synthesis of [2.n]metacyclophanes 270 via a [2 + 2] cycloaddition. Reagents and conditions: (i) Ac2...
Scheme 44: Synthesis of metacyclophane 273 by a [2 + 2 + 2] co-trimerization. Reagents and conditions: (i) [Rh...
Scheme 45: Synthesis of paracyclophane 276 via a [2 + 2 + 2] cycloaddition reaction. Reagents and conditions: ...
Scheme 46: Synthesis of cyclophane 278 via a [2 + 2 + 2] cycloaddition reaction. Reagents and conditions: (i) ...
Scheme 47: Synthesis of cyclophane 280 via a [2 + 2 + 2] cycloaddition. Reagents and conditions: (i) [(Rh(cod)(...
Scheme 48: Synthesis of taxane framework by a [2 + 2 + 2] cycloaddition. Reagents and conditions: (i) Cp(CO)2 ...
Scheme 49: Synthesis of cyclophane 284 and 285 via a [2 + 2 + 2] cycloaddition reaction. Reagents and conditio...
Scheme 50: Synthesis of pyridinophanes 293a,b and 294a,b via a [2 + 2 + 2] cycloaddition. Reagents and conditi...
Scheme 51: Synthesis of pyridinophanes 296 and 297 via a [2 + 2 + 2] cycloaddition. Reagents and conditions: (...
Scheme 52: Synthesis of triazolophane by a 1,3-dipolar cycloaddition. Reagents and conditions: (i) propargyl b...
Scheme 53: Synthesis of glycotriazolophane 309 by a click reaction. Reagents and conditions: (i) LiOH, H2O, Me...
Figure 11: Cyclophanes 310 and 311 prepared via click chemistry.
Scheme 54: Synthesis of cyclophane via the Dötz benzannulation. Reagents and conditions: (i) THF, 100 °C, 12 h...
Scheme 55: Synthesis of [6,6]metacyclophane by a Dötz benzannulation. Reagents and conditions: (i) THF, 100 °C...
Scheme 56: Synthesis of cyclophanes by a Dötz benzannulation. Reagents and conditions: (i) THF, 65 °C, 3 h; (i...
Scheme 57: Synthesis of muscopyridine (73) via an intramolecular DA reaction of ketene. Reagents and condition...
Scheme 58: Synthesis of bis[10]paracyclophane 336 via Diels–Alder reaction. Reagents and conditions: (i) DMAD,...
Scheme 59: Synthesis of [8]paracyclophane via DA reaction. Reagents and conditions: (i) maleic anhydride, 3–5 ...
Scheme 60: Biomimetic synthesis of (−)-longithorone A. Reagents and conditions: (i) Me2AlCl, CH2Cl2, −20 °C, 7...
Scheme 61: Synthesis of sporolide B (349) via a [4 + 2] cycloaddition reaction. Reagents and conditions: (i) P...
Scheme 62: Synthesis of the framework of (+)-cavicularin (352) via a [4 + 2] cycloaddition. Reagents and condi...
Scheme 63: Synthesis of oxazole-containing cyclophane 354 via Beckmann rearrangement. Reagents and conditions:...
Scheme 64: Synthesis of cyclophanes 360a–c via benzidine rearrangement. Reagents and conditions: (i) 356a–d, K2...
Scheme 65: Synthesis of cyclophanes 365a–c via benzidine rearrangement. Reagents and conditions: (i) BocNHNH2,...
Scheme 66: Synthesis of metacyclophane 367 via Ciamician–Dennstedt rearrangement. Reagents and conditions: (i)...
Scheme 67: Synthesis of cyclophane by tandem Claisen rearrangement and RCM as key steps. Reagents and conditio...
Scheme 68: Synthesis of cyclophane derivative 380. Reagents and conditions: (i) K2CO3, CH3CN, allyl bromide, r...
Scheme 69: Synthesis of metacyclophane via Cope rearrangement. Reagents and conditions: (i) MeOH, NaBH4, rt, 1...
Scheme 70: Synthesis of cyclopropanophane via Favorskii rearrangement. Reagents and conditions: (i) Br2, CH2Cl2...
Scheme 71: Cyclophane 389 synthesis via photo-Fries rearrangement. Reagents and conditions: (i) DMAP, EDCl/CHCl...
Scheme 72: Synthesis of normuscopyridine (223) via Schmidt rearrangement. Reagents and conditions: (i) ethyl s...
Scheme 73: Synthesis of crownophanes by tandem Claisen rearrangement. Reagents and conditions: (i) diamine, Et3...
Scheme 74: Attempted synthesis of cyclophanes via tandem Claisen rearrangement and RCM. Reagents and condition...
Scheme 75: Synthesis of muscopyridine via alkylation with 2,6-dimethylpyridine anion. Reagents and conditions:...
Scheme 76: Synthesis of cyclophane via Friedel–Craft acylation. Reagents and conditions: (i) CS2, AlCl3, 7 d, ...
Scheme 77: Pyridinophane 418 synthesis via Friedel–Craft acylation. Reagents and conditions: (i) 416, AlCl3, CH...
Scheme 78: Cyclophane synthesis involving the Kotha–Schölkopf reagent 421. Reagents and conditions: (i) NBS, A...
Scheme 79: Cyclophane synthesis involving the Kotha–Schölkopf reagent 421. Reagents and conditions: (i) BEMP, ...
Scheme 80: Cyclophane synthesis by coupling with TosMIC. Reagents and conditions: (i) (a) ClCH2OCH3, TiCl4, CS2...
Scheme 81: Synthesis of diaza[32]cyclophanes and triaza[33]cyclophanes. Reagents and conditions: (i) DMF, NaH,...
Scheme 82: Synthesis of cyclophane 439 via acyloin condensation. Reagents and conditions: (i) Na, xylene, 75%;...
Scheme 83: Synthesis of multibridged binuclear cyclophane 442 by aldol condensation. Reagents and conditions: ...
Scheme 84: Synthesis of various macrolactones. Reagents and conditions: (i) iPr2EtN, DMF, 77–83%; (ii) TBDMSCl...
Scheme 85: Synthesis of muscone and muscopyridine via Yamaguchi esterification. Reagents and conditions: (i) 4...
Scheme 86: Synthesis of [5]metacyclophane via a double elimination reaction. Reagents and conditions: (i) LiBr...
Figure 12: Cyclophanes 466–472 synthesized via Hofmann elimination.
Scheme 87: Synthesis of cryptophane via Baylis–Hillman reaction. Reagents and conditions: (i) methyl acrylate,...
Scheme 88: Synthesis of cyclophane 479 via double Chichibabin reaction. Reagents and conditions: (i) excess 478...
Scheme 89: Synthesis of cyclophane 483 via double Chichibabin reaction. Reagents and conditions: (i) 481, OH−;...
Scheme 90: Synthesis of cyclopeptide via an intramolecular SNAr reaction. Reagents and conditions: (i) TBAF, T...
Scheme 91: Synthesis of muscopyridine (73) via C-zip ring enlargement reaction. Reagents and conditions: (i) H...
Figure 13: Mechanism of the formation of compound 494.
Scheme 92: Synthesis of indolophanetetraynes 501a,b using the Nicholas reaction as a key step. Reagents and co...
Scheme 93: Synthesis of cyclophane via radical cyclization. Reagents and conditions: (i) cyclododecanone, phen...
Scheme 94: Synthesis of (−)-cylindrocyclophanes A (156) and (−)-cylindrocyclophanes F (155). Reagents and cond...
Scheme 95: Cyclophane synthesis via Wittig reaction. Reagents and conditions: (i) LiOEt (2.1 equiv), THF, −78 ...
Figure 14: Representative examples of cyclophanes synthesized via Wittig reaction.
Scheme 96: Synthesis of the [6]paracyclophane via isomerization of Dewar benzene. Reagents and conditions: (i)...
New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes
- Rym Hassani,
- Mahjoub Jabli,
- Yakdhane Kacem,
- Jérôme Marrot,
- Damien Prim and
- Béchir Ben Hassine
Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132
- )-di-μ-acetatobis[1-(4-isopropyloxazolin-2-yl)naphthalen-2-yl-C,N]dipalladium(II) (3) (Scheme 1). Unfortunately, complex dimer 3 was relatively unstable, so only its 1H NMR and FTIR data were performed. The metathesis of dimer 3 with lithium chloride in acetone afforded the more stable (S,S)-dimer 4 in
Graphical Abstract
Figure 1: Structure of Eriochrome Blue Black B.
Scheme 1: Cyclopalladation reactions of (S)-4-isopropyl-2-(naphthalen-1-yl)oxazoline.
Scheme 2: Synthesis of cyclopalladated complex from bis-oxazoline.
Figure 2: ORTEP drawing of the complex 8.
Scheme 3: Synthesis of the bis(oxazoline) coordinated complexes.
Figure 3: ORTEP drawing of the complex 9.
Figure 4: Change in color removal in the presence of different catalysts within 10 min (before filtration). T...
Figure 5: Change in color removal in the presence of different catalysts (after filtration over 10 min).
Figure 6: Evolution of the color degradation against time using Eriochrome plus H2O2, the complex plus H2O2 o...
Figure 7: Change of the concentration of the Erio solution with the variation of H2O2 dose.
Figure 8: Evolution of the color removal against initial dye concentration.
Figure 9: Change of the color removal versus temperature.
Figure 10: Recycling experiments for Erio removal (C0 = 30 ppm, 20 mL) in the presence of catalyst 9 at pH 7 a...
Scheme 4: Proposed mechanism of decolorization.
Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization
- Guillaume Moreira,
- Laurence Charles,
- Mohamed Major,
- Florence Vacandio,
- Yohann Guillaneuf,
- Catherine Lefay and
- Didier Gigmes
Beilstein J. Org. Chem. 2013, 9, 1589–1600, doi:10.3762/bjoc.9.181
- modification of cellulose polymer chains by NMP. Experimental Materials and general experimental details Triethylamine (Et3N, Aldrich, 99+%), acryloyl chloride (Aldrich, 97+%), D-glucose (Aldrich, 99.5%), D-cellobiose (Alfa Aesar, 98+%), lithium chloride (LiCl, Aldrich, 99+%), lithium bromide (LiBr, Aldrich
Graphical Abstract
Figure 1: Structure of the SG1, TEMPO and DBN nitroxides and the BlocBuilder MA alkoxyamine.
Figure 2: Key equilibrium between active and dormant species involved in the nitroxide-mediated (NMP) polymer...
Figure 3: Degradation of the SG1 nitroxide versus time in the presence of 0 (empty stars), 1 (filled squares)...
Figure 4: Degradation of the SG1 (triangles) and TEMPO (squares) nitroxides versus time in the presence of 0 ...
Figure 5: Degradation of the SG1 nitroxide versus time in DMA (filled squares), DMF (filled triangles), MeOH ...
Figure 6: Degradation of the SG1 nitroxide versus time in the presence of 0% of lithium salt in DMA (empty sq...
Figure 7: Degradation of the TEMPO nitroxide versus time in DMA in the presence of 0% lithium salt (empty squ...
Figure 8: NMP of styrene initiated by the BlocBuilder MA alkoxyamine at 120 °C in DMA without LiCl salt. (a) ...
Scheme 1: Synthesis of the cellobiose and SG1-based alkoxyamine (cello-SG1). The shown regioisomer exhibits a...
Figure 9: (a) Evolution of the number-average molar mass (Mn: filled symbol, linear fit: dash lines) and poly...
Scheme 2: (Reversible) redox system of nitroxide.
Figure 10: Cyclic voltammograms in DMF of (a) SG1 (10−2 M)/ NaClO4 (10−1 M) and (b) LiCl (10−2 M)/TBAPF6 (10−1...
Figure 11: Cyclic voltammograms of DMF/4.5 wt % LiBr solution heated at 80 °C for 30 min (plain line) and 14 h...
Scheme 3: Hydrolysis of DMA in the presence of LiCl.
Scheme 4: Disproportionation of nitroxide 1 by acid treatment.
Figure 12: Degradation of the nitroxides (SG1 and TEMPO) in the presence of HCl. (a) TEMPO ESR signal in the p...
Diastereoselective synthesis of nitroso acetals from (S,E)-γ-aminated nitroalkenes via multicomponent [4 + 2]/[3 + 2] cycloadditions promoted by LiCl or LiClO4
- Leandro Lara de Carvalho,
- Robert Alan Burrow and
- Vera Lúcia Patrocinio Pereira
Beilstein J. Org. Chem. 2013, 9, 838–845, doi:10.3762/bjoc.9.96
- only three diastereoisomers was obtained in good yield and useful reaction time. When lithium chloride solution 4.7 M in EtOH/H2O (3:1) (henceforth LCEW) was employed (Table 2, entry 2), the outcome was similar to that in Table 2, entry 1. Lithium chloride is not appreciably soluble in THF and for this
Graphical Abstract
Scheme 1: Reactivity of nitroalkenes and/or their respective nitronates in cycloaddition reactions.
Scheme 2: Synthetic route toward the chiral (S,E)-γ-aminated nitroalkenes 5a–c and their 1,3-diamine derivati...
Figure 1: ORTEP for nitroso acetal 11b.
Figure 2: 1D NOESY correlation between H2, H3a, H4 and H6 for all nitroso acetals.
Scheme 3: Transition-state models to stereoselective approaches in the multicomponent cycloadditions of 5a–c.
Scheme 4: Hydrogenolysis of 9c to pyrrolizidin-3-one 14c.
Synthesis of diverse indole libraries on polystyrene resin – Scope and limitations of an organometallic reaction on solid supports
- Kerstin Knepper,
- Sylvia Vanderheiden and
- Stefan Bräse
Beilstein J. Org. Chem. 2012, 8, 1191–1199, doi:10.3762/bjoc.8.132
- , one equiv of the respective 7-bromo-1H-indole-6-carboxymethyl-polystyrene is suspended in DMF (0.1 mmol/mL) together with 10.0 mol % bis(triphenylphosphine)palladium(II) chloride, 15.0 equiv of lithium chloride and one equiv of triphenylphosphine. Then, three equiv of tributyl(vinyl)tin are added and
Graphical Abstract
Scheme 1: Diverse synthesis of indoles using Bartoli reactions. aSee [24].
Figure 1: Nitroarenes on solid supports. In red: Nitroarenes failed to give indoles. aResin has been reported...
Figure 2: Temperature optimization with Grignard reagent 2{b}.
Figure 3: Temperature optimization with Grignard reagent 2{a}. Isolated yield.
Figure 4: Optimization studies of ester 1{h} with a Grignard reagent 2{d} to give indole 3{h,d} and methyl 3-...
Scheme 2: Stille reaction on solid supports.
Scheme 3: Suzuki reaction on solid supports.
Scheme 4: Sonogashira–Hagihara reaction on solid supports.
Asymmetric total synthesis of smyrindiol employing an organocatalytic aldol key step
- Dieter Enders,
- Jeanne Fronert,
- Tom Bisschops and
- Florian Boeck
Beilstein J. Org. Chem. 2012, 8, 1112–1117, doi:10.3762/bjoc.8.123
- Knochel's published modification [14] of this reaction using a lanthanum(III) chloride bis(lithium chloride) complex solution and a methyl Grignard reagent proved to be robust and produced the desired 1,3-diol 15 in high yields (87%). The 1,3-diol was found to be sensitive towards condensation to the
Graphical Abstract
Figure 1: Furocoumarins.
Scheme 1: Synthesis of smyrindiol (1) by Grande et al.
Scheme 2: Synthesis of smyrindiol by Snider et al.
Scheme 3: Proline-catalyzed intramolecular aldol reaction of O-acetonyl-salicylaldehydes.
Scheme 4: First retrosynthetic analysis.
Scheme 5: Attempted proline catalyzed aldol reaction.
Scheme 6: Second retrosynthetic analysis.
Scheme 7: Asymmetric total synthesis of smyrindiol (1).
Synthesis of novel 5-alkyl/aryl/heteroaryl substituted diethyl 3,4-dihydro-2H-pyrrole-4,4-dicarboxylates by aziridine ring expansion of 2-[(aziridin-1-yl)-1-alkyl/aryl/heteroaryl-methylene]malonic acid diethyl esters
- Satish S. More,
- T. Krishna Mohan,
- Y. Sateesh Kumar,
- U. K. Syam Kumar and
- Navin B. Patel
Beilstein J. Org. Chem. 2011, 7, 831–838, doi:10.3762/bjoc.7.95
- , 8 and 9). The hydrolytic decarboxylation of diethyl 3,4-dihydro-5-phenyl-2H-pyrrole-4,4-dicarboxylate (21e) was carried out in wet DMSO in the presence of lithium chloride at 140–150 °C (Krapcho’s method) for 3 h to give 2-phenylpyrroline (23) in about 84% yield. When this reaction was carried out
Graphical Abstract
Figure 1: Natural products containing 2-substituted pyrroline residues in their core structural units.
Figure 2: Natural products containing 2-substituted pyrrolidine residues in their core structural units.
Scheme 1: Iodide ion mediated ring expansion of N-vinylaziridines.
Scheme 2: Synthesis of N-vinyl substituted aziridines and their ring expansion to pyrrolines. Reagents and co...
Scheme 3: Hydrolytic decarboxylation. Reagents and conditions: i) DMSO, LiCl catalytic water, 140–150 °C, 3 h...
Scheme 4: Reduction and aromatization of 2-substituted pyrrolines.
Scheme 5: Reaction conditions: i) THF, rt, 3 h; ii) NaI, acetone, rt, overnight.
Scheme 6: Reaction conditions: i) THF, TEA, rt; ii) NaI, acetone, rt, overnight.
The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines
- Matthew J. McGrath and
- Carsten Bolm
Beilstein J. Org. Chem. 2007, 3, No. 33, doi:10.1186/1860-5397-3-33
- potential for use in asymmetric catalysis. Results Asymmetric deprotonation of N-trialkylsilyl dimethyl sulfoximines with either enantiomer of lithium N,N-bis(1-phenylethyl)amide in the presence of lithium chloride affords enantioenriched sulfoximines on electrophilic trapping. Ketones, ketimines
- ). Deprotonation with lithium amide (R,R)-5 in the presence of lithium chloride (conveniently generated in situ by deprotonation of the amine hydrochloride with n-BuLi [20][21] gave an inseparable mixture of 2a and bis(1-phenylethyl)amine, encouragingly however, HPLC examination of the mixture using a chiral
- TMSCl quenching when sulfoximine 1b was first lithiated by treatment with n-BuLi followed by addition of a solution of (S,S)-bis-N,N-(1-phenylethyl)amine and lithium chloride (Scheme 5). In an analogous reaction, enantioenriched lithiated sulfoxides racemised via a reversible disproportionation to the
Graphical Abstract
Scheme 1: Desymmetrisation of N-trialkylsilyldimethylsulfoximines using chiral bases
Scheme 2: Preparation of N-trialkylsilyl dimethyl sulfoximine derivatives
Figure 1: The diamine (-)-sparteine and three chiral lithium amide bases.
Scheme 3: Preparation of vinyl sulfoximines
Figure 2: Selected NMR Characteristics of sulfoximine amides 12, 13 and 14.
Scheme 4: Preparation of O-methyl mandelamide derivatives (S,R)-12 and (R,R)-12
Scheme 5: The influence of (S,S)-bis(1-phenylethyl)amine on the ee of 1b
