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Search for "dimethyl acetylenedicarboxylate (DMAD)" in Full Text gives 13 result(s) in Beilstein Journal of Organic Chemistry.
The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition
- Xiu-Yu Chen,
- Hui Zheng,
- Ying Han,
- Jing Sun and
- Chao-Guo Yan
Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73
- ]naphthyridine and 2-azabicyclo[4.2.0]octa-3,7-diene derivatives. Results and Discussion Initially, the reaction conditions were briefly examined by using isoquinoline (1), dimethyl acetylenedicarboxylate (DMAD, 2) and 5,6-unsubstituted 1,4-dihydropyridine 3 as standard reaction (Table 1). The three-component
Graphical Abstract
Scheme 1: Various cycloaddition reactions of 5,6-unsymmetric 1,4-dihydropyridines.
Figure 1: Single crystal structure of the compound 4k.
Figure 2: Single crystal structure of compound 5a.
Figure 3: Single crystal structure of compound 6f.
Scheme 2: Plausible reaction mechanism for the various products 4, 5, and 6.
Synthesis of functionalized imidazo[4,5-e]thiazolo[3,2-b]triazines by condensation of imidazo[4,5-e]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5-e]thiazolo[2,3-c]triazines
- Alexei N. Izmest’ev,
- Dmitry B. Vinogradov,
- Natalya G. Kolotyrkina,
- Angelina N. Kravchenko and
- Galina A. Gazieva
Beilstein J. Org. Chem. 2021, 17, 1141–1148, doi:10.3762/bjoc.17.87
- with asymmetric substrates is the high regioselectivity of the cyclizations of intermediate Michael adducts at one of several reactive nitrogen atoms. For example, reported by Giannola et al. [21], the reaction of 3-thioxo-1,2,4-triazin-5-ones 1 with dimethyl acetylenedicarboxylate (DMAD) leads to the
Graphical Abstract
Figure 1: Biologically active compounds having thiazolidin-4-one and thiazolo-1,2,4-triazine units.
Scheme 1: Regioselectivity of the cyclization of 3-thioxo-1,2,4-triazin-5-ones 1 with DMAD (A) and general co...
Scheme 2: Synthesis of imidazo[4,5-e]thiazolo[3,2-b]triazine derivatives 4a–n by the reaction of imidazo[4,5-...
Scheme 3: Reaction of imidazo[4,5-e]thiazolo[3,2-b]triazine 4h with aqueous KOH.
Scheme 4: Rearrangement of imidazo[4,5-e]thiazolo[3,2-b]triazines 4a–n into imidazo[4,5-e]thiazolo[2,3-c]tria...
Scheme 5: One-pot synthesis of compounds 5a,b,h,i from imidazo[4,5-e]triazines 3a,b.
Scheme 6: Plausible mechanism of the formation and the rearrangement of compounds 4 into isomers 5.
Figure 2: 1H NMR spectra of compounds 4h and 5h in DMSO-d6 in the region of 3.5–8.8 ppm.
Figure 3: X-ray crystal structure of compound 5i.
Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol
- Ekaterina E. Stepanova,
- Maksim V. Dmitriev and
- Andrey N. Maslivets
Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193
- work [9] and found that the correct structure of the studied compound was structure B (CCDC 2019497) (Scheme 1). In fact, for now, four approaches to BTAs III are known [21][22][23][24][25] (Scheme 2). They include the reaction of dimethyl acetylenedicarboxylate (DMAD) with o-aminothiophenol (1a) on
Graphical Abstract
Figure 1: Enaminones fused to heterocyclic moieties.
Scheme 1: Reported structure A of assayed compound [9] and its correct structure B.
Scheme 2: Known synthetic approaches to BTAs III.
Scheme 3: General synthetic approaches to enaminones I and II.
Scheme 4: Reported reactions of acylpyruvic acids or their esters IV with o-aminothiophenol (1a) [27,28].
Scheme 5: Plausible mechanism of the reaction of acylpyruvic acid 2a with o-aminothiophenol (1a) in the prese...
Scheme 6: The substrate scope of the optimized approach to BTAs 3a–n. Procedure: to a cooled to 0–5 °C stirri...
Scheme 7: The substrate scope of the optimized approach to compounds 4a–n. Procedure: to a stirring solution ...
Scheme 8: Plausible scheme of the formation of diketone 6.
An overview of the cycloaddition chemistry of fulvenes and emerging applications
- Ellen Swan,
- Kirsten Platts and
- Anton Blencowe
Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209
- dependent mostly on its substituents (e.g., EWG or EDG) relative to the other reactants [6][42][45][67][103][153][230]. Maleimides (including maleic anhydride) [55][71][92][96][150][176][177][179][180][181][182][183][184][186][192][229][231], dimethyl acetylenedicarboxylate (DMAD) and p-benzoquinone [60
- (i) maleimide derivatives, (ii) dimethyl acetylenedicarboxylate (DMAD) and (iii) p-benzoquinones. Generic schemes showing pentafulvenes participating as dienophiles in Diels–Alder cycloadditions with (i) o-benzoquinones and (ii) polyhalogenated cyclopentadienes. Reaction of 8,8-dicyanoheptafulvene
Graphical Abstract
Figure 1: General structure of fulvenes, named according to the number of carbon atoms in their ring. Whilst ...
Figure 2: Generic structures of commonly referenced heteropentafulvenes, named according to the heteroatom su...
Scheme 1: Resonance structures of (a) pentafulvene and (b) heptafulvene showing neutral (1 and 2), dipolar (1a...
Scheme 2: Resonance structures of (a) pentafulvenes and (b) heptafulvenes showing the influence of EDG and EW...
Scheme 3: Reaction of 6,6-dimethylpentafulvene with singlet state oxygen to form an enol lactone via the mult...
Scheme 4: Photosensitized oxygenation of 8-cyanoheptafulvene with singlet state oxygen to afford 1,4-epidioxi...
Figure 3: A representation of HOMO–LUMO orbitals of pentafulvene and the influence of EWG and EDG substituent...
Scheme 5: Reactions of (a) 6,6-dimethylpentafulvene participating as 2π and 4π components in cycloadditions w...
Scheme 6: Proposed mechanism for the [6 + 4] cycloaddition of tropone with dimethylfulvene via an ambimodal [...
Scheme 7: Triafulvene dimerization through the proposed 'head-to-tail' mechanism. The dipolar transition stat...
Scheme 8: Dimerization of pentafulvenes via a Diels–Alder cycloaddition pathway whereby one fulvene acts as a...
Scheme 9: Dimerization of pentafulvenes via frustrated Lewis pair chemistry as reported by Mömming et al. [116].
Scheme 10: Simplified reaction scheme for the formation of kempane from an extended-chain pentafulvene [127].
Scheme 11: The enantioselective (>99% ee), asymmetric, catalytic, intramolecular [6 + 2] cycloaddition of fulv...
Scheme 12: Intramolecular [8 + 6] cycloaddition of the heptafulvene-pentafulvene derivative [22,27].
Scheme 13: Reaction scheme for (a) [2 + 2] cycloaddition of 1,2-diphenylmethylenecyclopropene and 1-diethylami...
Scheme 14: Diels–Alder cycloaddition of pentafulvenes derivatives participating as dienes with (i) maleimide d...
Scheme 15: Generic schemes showing pentafulvenes participating as dienophiles in Diels–Alder cycloadditions wi...
Scheme 16: Reaction of 8,8-dicyanoheptafulvene and styrene derivatives to afford [8 + 2] and [4 + 2] cycloaddu...
Scheme 17: Reaction of 6-aminofulvene and maleic anhydride, showing observed [6 + 2] cycloaddition; the [4 + 2...
Scheme 18: Schemes for Diels–Alder cycloadditions in dynamic combinatorial chemistry reported by Boul et al. R...
Scheme 19: Polymerisation and dynamer formation via Diels–Alder cycloaddition between fulvene groups in polyet...
Scheme 20: Preparation of hydrogels via Diels–Alder cycloaddition with fulvene-conjugated dextran and dichloro...
Scheme 21: Ring-opening metathesis polymerisation of norbornene derivatives derived from fulvenes and maleimid...
Domino ring-opening–ring-closing enyne metathesis vs enyne metathesis of norbornene derivatives with alkynyl side chains. Construction of condensed polycarbocycles
- Ritabrata Datta and
- Subrata Ghosh
Beilstein J. Org. Chem. 2018, 14, 2708–2714, doi:10.3762/bjoc.14.248
- situ with dimethyl acetylenedicarboxylate (DMAD). In case the Diels–Alder reaction would take place through the triene 9a the tetracyclic structure 12a would be formed. However, 13C NMR spectra of the product revealed the presence of eight methylene carbon signals at δ 28.6, 28.9, 30.9, 33.5, 36.7
Graphical Abstract
Scheme 1: Metathesis of norbornene derivatives.
Figure 1: Structures of retigeranic acids A (1a) and B (1b).
Scheme 2: Synthesis plan.
Scheme 3: Metathesis of norbornene derivatives 7a and 7b.
Figure 2: ORTEP of compound 13 (ellipsoids at 30% probability).
Scheme 4: Metathesis of the norbornene derivative 17.
Figure 3: Probable metathesis intermediates.
Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps
- Sambasivarao Kotha,
- Milind Meshram and
- Chandravathi Chakkapalli
Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223
- with G-I catalyst 1 under ethylene, which resulted in the formation of the dienes 97a (63%) and 97b (83%, Scheme 15). Further, treatment of dienes 97a,b with dimethyl acetylenedicarboxylate (DMAD, 98) separately delivered the corresponding cycloadducts. Subsequently, aromatization was achieved by using
Graphical Abstract
Figure 1: Various catalysts used for metathesis reactions.
Scheme 1: SM coupling and RCM protocol to substituted indene derivative 10.
Scheme 2: Synthesis of polycycles via SM and RCM approach.
Figure 2: Various angucyclines.
Scheme 3: SM coupling and RCM protocol to the benz[a]anthracene skeleton 26.
Scheme 4: Synthesis of substituted spirocycles via RCM and SM sequence.
Scheme 5: Synthesis of highly functionalized bis-spirocyclic derivative 37.
Scheme 6: Synthesis of spirofluorene derivatives via RCM and SM coupling sequence.
Scheme 7: Synthesis of truxene derivatives via RCM and SM coupling.
Scheme 8: Synthesis of substituted isoquinoline derivative via SM and RCM protocol.
Scheme 9: Synthesis to 8-aryl substituted coumarin 64 via RCM and SM sequence.
Scheme 10: Synthesis of cyclic sulfoximine 70 via SM and RCM as key steps.
Scheme 11: Synthesis of 1-benzazepine derivative 75 via SM and RCM as key steps.
Scheme 12: Synthesis of naphthoxepine derivative 79 via RCM followed by SM coupling.
Scheme 13: Sequential CM and SM coupling approach to Z-stilbene derivative 85.
Scheme 14: Synthesis of substituted trans-stilbene derivatives via SM coupling and RCM.
Scheme 15: Synthesis of biaryl derivatives via sequential EM, DA followed by SM coupling.
Scheme 16: Synthesis of the dibenzocyclooctadiene core of schisandrene.
Scheme 17: Synthesis of cyclophane 115 via SM coupling and RCM as key steps.
Scheme 18: Synthesis of cyclophane 120 and 122 via SM coupling and RCM as key steps.
Scheme 19: Synthesis of cyclophanes via SM and RCM.
Scheme 20: Synthesis of MK-6325 (141) via RCM and SM coupling.
[3 + 2]-Cycloaddition reaction of sydnones with alkynes
- Veronika Hladíková,
- Jiří Váňa and
- Jiří Hanusek
Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113
- of substituted 1,3,4-tri- or 1,3,4,5-tetrasubstituted pyrazoles [1][2][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] or indazoles. Dimethyl acetylenedicarboxylate (DMAD, R3 = COOMe) or its analogues (diethyl; R3
Graphical Abstract
Scheme 1: Thermal reaction of sydnones with symmetrical alkynes.
Scheme 2: Reaction of sydnones with strained cycloalkynes.
Scheme 3: Reaction of sydnones with didehydrobenzenes.
Scheme 4: Formation of isomeric pyrazole dicarboxylates.
Scheme 5: Mechanism of thermal cycloaddition between sydnones and alkynes.
Scheme 6: Mechanism of photochemical reaction of sydnones with symmetrical alkynes.
Scheme 7: HOMO–LUMO diagram for thermal [3 + 2]-cycloaddition of sydnones with alkynes.
Scheme 8: Synthetic strategy leading to 1,2-disubstituted pyrazoles.
Scheme 9: Unsuccessful reaction with phenylpropiolic acid.
Scheme 10: Synthetic strategy leading to 1,4,5-trisubstituted pyrazoles.
Scheme 11: Reaction of sydnones carrying in position 4- six-membered 2-N-heterocyclic ring.
Scheme 12: Strain-promoted sydnone alkyne cycloaddition (SPSAC).
Scheme 13: Synthesis of a key intermediate of niraparib.
Scheme 14: Reaction of sydnones with 1,3-/1,4-benzdiyne equivalents.
Scheme 15: Reaction of sydnones with heterocyclic strained cycloalkynes.
Scheme 16: Mono-copper catalyzed cycloaddition reaction.
Scheme 17: Di-copper catalyzed cycloaddition reaction.
Recent applications of ring-rearrangement metathesis in organic synthesis
- Sambasivarao Kotha,
- Milind Meshram,
- Priti Khedkar,
- Shaibal Banerjee and
- Deepak Deodhar
Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199
- acetylenedicarboxylate (DMAD, 129) to generate the tetracyclic system 130 (Scheme 27). To design synthetically challenging oxa-bowls, Kotha and Ravikumar [31] have utilized the RRM and ERRM of extended norbornene systems. The key building blocks such as 133 and 134 were prepared from a readily available DA adduct 131
- obtained by RRM of 124 using catalyst 1 under ethylene (24) atmosphere. Interestingly, the diene building block 128, produced by employing an enyne-ring rearrangement metathesis (ERRM) sequence, was subjected to a DA reaction in refluxing toluene with various dienophiles such as dimethyl
Graphical Abstract
Figure 1: Ruthenium alkylidene catalysts used in RRM processes.
Figure 2: General representation of various RRM processes.
Figure 3: A general mechanism for RRM process.
Scheme 1: RRM of cyclopropene systems.
Scheme 2: RRM of cyclopropene with catalyst 2. (i) catalyst 2 (2.5 mol %), ethylene (24, 1 atm), (ii) toluene...
Scheme 3: RRM of various cyclopropene derivatives with catalyst 2. (i) catalyst 2 (2.5 mol %), CH2Cl2 (c = 0....
Scheme 4: RRM of substituted cyclopropene system with catalyst 2.
Scheme 5: RRM of cyclobutene system with catalyst 2.
Scheme 6: RRM approach to various bicyclic compounds.
Scheme 7: RRM approach to erythrina alkaloid framework.
Scheme 8: ROM–RCM sequence to lactone derivatives.
Scheme 9: RRM protocol towards the synthesis of lactone derivative 58.
Scheme 10: RRM protocol towards the asymmetric synthesis of asteriscunolide D (61).
Scheme 11: RRM strategy towards the synthesis of various macrolide rings.
Scheme 12: RRM protocol to dipiperidine system.
Scheme 13: RRM of cyclopentene system to generate the cyclohexene systems.
Scheme 14: RRM of cyclopentene system 74.
Scheme 15: RRM approach to compound 79.
Scheme 16: RRM approach to spirocycles.
Scheme 17: RRM approach to bicyclic dihydropyrans.
Scheme 18: RCM–ROM–RCM cascade using non strained alkenyl heterocycles.
Scheme 19: First ROM–RCM–ROM–RCM cascade for the synthesis of trisaccharide 97.
Scheme 20: RRM of cyclohexene system.
Scheme 21: RRM approach to tricyclic spirosystem.
Scheme 22: RRM approach to bicyclic building block 108a.
Scheme 23: ROM–RCM protocol for the synthesis of the bicyclo[3.3.0]octene system.
Scheme 24: RRM protocol to bicyclic enone.
Scheme 25: RRM protocol toward the synthesis of the tricyclic system 118.
Scheme 26: RRM approach toward the synthesis of the tricyclic enones 122a and 122b.
Scheme 27: Synthesis of tricyclic and tetracyclic systems via RRM protocol.
Scheme 28: RRM protocol towards the synthesis of tetracyclic systems.
Scheme 29: RRM of the propargylamino[2.2.1] system.
Scheme 30: RRM of highly decorated bicyclo[2.2.1] systems.
Scheme 31: RRM protocol towards fused tricyclic compounds.
Scheme 32: RRM protocol to functionalized tricyclic systems.
Scheme 33: RRM approach to functionalized polycyclic systems.
Scheme 34: Sequential RRM approach to functionalized tricyclic ring system 166.
Scheme 35: RRM protocol to functionalized CDE tricyclic ring system of schintrilactones A and B.
Scheme 36: Sequential RRM approach to 7/5 fused bicyclic systems.
Scheme 37: Sequential ROM-RCM protocol for the synthesis of bicyclic sugar derivatives.
Scheme 38: ROM–RCM sequence of the norbornene derivatives 186 and 187.
Scheme 39: RRM approach toward highly functionalized bridge tricyclic system.
Scheme 40: RRM approach toward highly functionalized tricyclic systems.
Scheme 41: Synthesis of hexacyclic compound 203 by RRM approach.
Scheme 42: RRM approach toward C3-symmetric chiral trimethylsumanene 209.
Scheme 43: Triquinane synthesis via IMDA reaction and RRM protocol.
Scheme 44: RRM approach to polycyclic compounds.
Scheme 45: RRM strategy toward cis-fused bicyclo[3.3.0]carbocycles.
Scheme 46: RRM protocol towards the synthesis of bicyclic lactone 230.
Scheme 47: RRM approach to spiro heterocyclic compounds.
Scheme 48: RRM approach to spiro heterocyclic compounds.
Scheme 49: RRM approach to regioselective pyrrolizidine system 240.
Scheme 50: RRM approach to functionalized bicyclic derivatives.
Scheme 51: RRM approach to tricyclic derivatives 249 and 250.
Scheme 52: RRM approach to perhydroindoline derivative and spiro system.
Scheme 53: RRM approach to bicyclic pyran derivatives.
Scheme 54: RRM of various functionalized oxanorbornene systems.
Scheme 55: RRM to assemble the spiro fused-furanone core unit. (i) 129, benzene, 55 °C, 3 days; (ii) Ph3P=CH2B...
Scheme 56: RRM protocol to norbornenyl sultam systems.
Scheme 57: Ugi-RRM protocol for the synthesis of 2-aza-7-oxabicyclo system.
Scheme 58: Synthesis of spiroketal systems via RRM protocol.
Scheme 59: RRM approach to cis-fused heterotricyclic system.
Scheme 60: RRM protocol to functionalized bicyclic systems.
Scheme 61: ROM/RCM/CM cascade to generate bicyclic scaffolds.
Scheme 62: RCM of ROM/CM product.
Scheme 63: RRM protocol to bicyclic isoxazolidine ring system.
Scheme 64: RRM approach toward the total synthesis of (±)-8-epihalosaline (300).
Scheme 65: Sequential RRM approach to decalin 304 and 7/6 fused 305 systems.
Scheme 66: RRM protocol to various fused carbocyclic derivatives.
Scheme 67: RRM to cis-hydrindenol derivatives.
Scheme 68: RRM protocol towards the cis-hydrindenol derivatives.
Scheme 69: RRM approach toward the synthesis of diversed polycyclic lactams.
Scheme 70: RRM approach towards synthesis of hexacyclic compound 324.
Scheme 71: RRM protocol to generate luciduline precursor 327 with catalyst 2.
Scheme 72: RRM protocol to key building block 330.
Scheme 73: RRM approach towards the synthesis of key intermediate 335.
Scheme 74: RRM protocol to highly functionalized spiro-pyran system 339.
Scheme 75: RRM to various bicyclic polyether derivatives.
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
- acetylenedicarboxylate (DMAD) to deliver compounds 332a,b (77%). These DA adducts were irradiated in diethyl ether/dichloromethane (5:1) to offer the corresponding bioxaquadricyclane 333, subsequent thermolysis gave the bioxepine 334 (81%). Finally, aromatization of bioxepine 334 with trifluoroacetic acid (TFA
- muscopyridine (73, 89%). [4 + 2] Cycloaddition (Diels–Alder reaction): In 2003, Tochtermann and co-workers [193] have synthesized a bis[10]paracyclophane with two chiral planes and one chiral axis via the DA reaction as a key step. The bifuran derivative 331 was subjected to a DA sequence with dimethyl
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)...
Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles
- Grzegorz Mlostoń,
- Paulina Grzelak,
- Maciej Mikina,
- Anthony Linden and
- Heinz Heimgartner
Beilstein J. Org. Chem. 2015, 11, 576–582, doi:10.3762/bjoc.11.63
- sulfones. Keywords: dimethyl acetylenedicarboxylate (DMAD); hetero-Diels–Alder reactions; high pressure reactions; methyl propiolate; thioketones; thiopyrans; Introduction A series of recent publications evidence that, in contrast to earlier opinions, thioketones are useful building blocks for the
Graphical Abstract
Scheme 1: Hetero-Diels–Alder reaction of thiobenzophenone (1a) with dimethyl acetylenedicarboxylate (2a) [10].
Scheme 2: Synthesis of polycyclic thiopyrans via the hetero-Diels–Alder reaction/1,3-hydrogen shift sequence.
Figure 1: ORTEP Plot [19] of the molecular structure of 4b, drawn using 50% probability displacement ellipsoids.
Scheme 3: Reactions of aryl/hetaryl thioketones with methyl propiolate (Table 1).
Scheme 4: Oxidation of selected thiopyrans 4 and 5 to give the corresponding sulfones.
Figure 2: ORTEP Plot [19] of the molecular structure of one of the symmetry-independent molecules of 6d, drawn us...
New highlights of the syntheses of pyrrolo[1,2-a]quinoxalin-4-ones
- Emilian Georgescu,
- Alina Nicolescu,
- Florentina Georgescu,
- Florina Teodorescu,
- Daniela Marinescu,
- Ana-Maria Macsim and
- Calin Deleanu
Beilstein J. Org. Chem. 2014, 10, 2377–2387, doi:10.3762/bjoc.10.248
- -(methoxycarbonylmethyl)benzimidazolium bromides with dimethyl acetylenedicarboxylate (DMAD) in presence of K2CO3 in DMF [7] or in presence of triethylamine in acetonitrile [8] give a mixture of pyrrolo[1,2-a]benzimidazole (2–7%) and a compound whose formation involves the loss of an alcohol molecule for which different
Graphical Abstract
Scheme 1: Synthesis of pyrrolo[1,2-a]quinoxalin-4-ones 4 and pyrrolo[1,2-a]benzimidazoles 5.
Scheme 2: Reaction pathway leading to the formation of pyrrolo[1,2-a]quinoxalin-4-ones 4 and pyrrolo[1,2-a]be...
Scheme 3: Novel synthetic pathway towards pyrrolo[1,2-a]quinoxalin-4-ones 10.
Figure 1: Undecoulpled H,C-HSQC spectrum for compound 5h.
Figure 2: Individual 1H signal assignments based on 13C traces from H,C-undecoulpled-HSQC spectrum around the...
Figure 3: NOE response as cross peaks between carbethoxy group protons and protons from positions 2 and 8 of ...
Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine
- Marc Enßle,
- Stefan Buck,
- Roland Werz and
- Gerhard Maas
Beilstein J. Org. Chem. 2012, 8, 433–440, doi:10.3762/bjoc.8.49
- -phthalimidocarboxylic esters [18][19], treatment of diazoester 8a with catalytic Rh2(OAc)4 in the presence of an equimolar amount of N-phenylmaleimide (NPI) or dimethyl acetylenedicarboxylate (DMAD) produced the cycloaddition products 18 and 19, respectively (Scheme 7). The signal sets of sulfonium ylides 12aA and 12aB
Graphical Abstract
Scheme 1: Synthesis of cyclic sulfonium ylides 2; n = 0–3.
Scheme 2: Non-carbenoid formation of sulfonium ylide 4.
Scheme 3: Conditions: (a) phthalic anhydride, NEt3 (10 mol %), toluene, reflux, 2 h; (b) 1. carbonyldiimidazo...
Scheme 4: Rh(II)-catalysed carbenoid reactions of diazoesters 8a,b.
Figure 1: Proposed relative configurations of the diastereomeric cyclic sulfonium ylides 12aA and 12aB. 1H NM...
Scheme 5: Endo transition state for [3 + 3]-dimerisation of carbonyl ylide 14.
Scheme 6: Rh(II)-catalysed carbenoid reactions of diazoester 8c.
Scheme 7: Tandem cyclisation/intermolecular cycloaddition of diazoester 8a. Conditions: (a) Rh2(OAc)4 (3 mol ...
Scheme 8: Carbenoid formation of sulfonium ylides from diazoesters 11a,b. Conditions: (a) Rh2(OAc)4 (3 mol %)...
Trapping evidence for the thermal cyclization of di-(o-acetylphenyl)acetylene to 3,3'-dimethyl- 1,1'-biisobenzofuran
- Charles P. Casey,
- Neil A. Strotman and
- Ilia A. Guzei
Beilstein J. Org. Chem. 2005, 1, No. 18, doi:10.1186/1860-5397-1-18
- Charles P. Casey Neil A. Strotman Ilia A. Guzei University of Wisconsin-Madison, Madison, WI 53706 10.1186/1860-5397-1-18 Abstract The reaction of di-(o-acetylphenyl)acetylene (1) with excess dimethyl acetylenedicarboxylate (DMAD) produced bis-DMAD adducts meso-3 and rac-3. This transformation is
- decomposition process. Here we report evidence for a bicyclization reaction of 1 leading to the first biisobenzofuran, and its trapping by reaction with dimethyl acetylenedicarboxylate (DMAD). An X-ray crystal structure of the resulting bis Diels-Alder adduct of this highly unstable isobenzofuran is reported
Graphical Abstract
Scheme 1: Thermal cyclization of η2-(o-ethynylbenzoyl)rhenium complexes to rhenium isobenzofuryl carbene comp...
Scheme 2: Reagents and conditions: (a) Me3SiC≡CH, Pd(PPh3)4, CuI, Et3N, toluene, 40°C, 22 h, 99 %; (b) KF, Me...
Scheme 3: Possible thermal bicyclization of 1 to A.
Scheme 4: Thermal rearrangement of a 2,6-alkadien-4-yn-1,8-dialdehyde to a bifuran.
Scheme 5: Photochemical cyclization to a bifuran.
Scheme 6: Trapping of A by DMAD to form Diels-Alder adducts meso-3 and rac-3.
Figure 1: X-ray crystal structure of meso-3.
Scheme 7: Possible stepwise mechanism for rearrangement of 1 to A.
Scheme 8: Possible concerted mechanism for rearrangement of 1 to A.
Scheme 9: Ring closures of o-acyl phenylcarbenes to isobenzofurans.
Scheme 10: Ring opening of 2-furylcarbenes to alk-2-en-4-yn-1-ones.
Scheme 11: Coupled coarctate cyclization and 6π electrocyclization.
