Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation
- Sambasivarao Kotha,
- Gaddamedi Sreevani,
- Lilya U. Dzhemileva,
- Milyausha M. Yunusbaeva,
- Usein M. Dzhemilev and
- Vladimir A. D’yakonov
Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269
Graphical Abstract
Scheme 1: Conventional method of synthesis of thiazolidine-2,4-dione derivatives.
Scheme 2: [2 + 2 + 2] Cyclotrimerization of N-methylthiazolidinedione.
Scheme 3: Unexpected product 5b obtained in the attempted NH-protection of thiazolidinedione with (Boc)2O.
Figure 1: Comparison of 13C NMR values of 9 and 5b.
Scheme 4: [2 + 2 + 2] Cyclotrimerization of dipropargylthiazolidinediones with propargyl halides.
Scheme 5: Formation of sultine 13 from compound 8b followed by DA reaction.
Scheme 6: Dipropargylation of 2,4-thiazolidinedione derivatives.
Scheme 7: [2 + 2 + 2] Cycloaddition in the presence of Wilkinson’s catalyst.
Scheme 8: N-Ester derivative 18 hydrolysis to N-acid derivative 22.
Scheme 9: Synthesis of triazolo derivative 24 via click reaction.
Synthesis of C3-symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step
- Sambasivarao Kotha and
- Saidulu Todeti
Beilstein J. Org. Chem. 2019, 15, 371–377, doi:10.3762/bjoc.15.33
Graphical Abstract
Figure 1: Exemplar C3-symmetric peptide scaffolds reported in the literature.
Scheme 1: Preparation of compound 7 from L-serine (3).
Scheme 2: Preparation of the trimerized product 9.
Scheme 3: Synthesis of compound 11 via Negishi cross-coupling reaction.
Scheme 4: Synthesis of C3-symmetric trimers 12, 13 and 14.
Design and synthesis of C3-symmetric molecules bearing propellane moieties via cyclotrimerization and a ring-closing metathesis sequence
- Sambasivarao Kotha,
- Saidulu Todeti and
- Vikas R. Aswar
Beilstein J. Org. Chem. 2018, 14, 2537–2544, doi:10.3762/bjoc.14.230
Graphical Abstract
Figure 1: Various alkaloids containing propellane frame work.
Scheme 1: Synthesis of the star-shaped norbornene derivative 11 via trimerization.
Figure 2: Selected list of ruthenium-based catalysts used for ROM.
Scheme 2: Synthesis of the C3-symmetric molecule 15 bearing propellane moieties via trimerization and RCM.
Scheme 3: Synthesis of C3-symmetric molecule 21 bearing propellane moieties via trimerization and RCM.
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
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.
Bridgehead vicinal diallylation of norbornene derivatives and extension to propellane derivatives via ring-closing metathesis
- Sambasivarao Kotha and
- Rama Gunta
Beilstein J. Org. Chem. 2016, 12, 1877–1883, doi:10.3762/bjoc.12.177
Graphical Abstract
Figure 1: Retrosynthetic approach to propellane derivatives.
Scheme 1: Synthesis of the propellane derivative 1a via RCM.
Scheme 2: Garratts work on alkylation of norbornene with retention of configuration.
Figure 2: The molecular structure of 1a, with displacement ellipsoids drawn at the 50% probability level.
Scheme 3: Control experiment carried out to probe the configuration of 2a.
Figure 3: Crystal structure of compound 15 showing 50% displacement ellipsoids.
Scheme 4: RCM of the compound 2aa'.
Scheme 5: RCM approach to the propellane derivative 1b.
Figure 4: The molecular structures of the compounds 2b (left) and 1b (right) showing 30% displacement ellipso...
Scheme 6: Construction of the propellane derivative 1bb' using RCM.
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
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.
Design and synthesis of propellane derivatives and oxa-bowls via ring-rearrangement metathesis as a key step
- Sambasivarao Kotha and
- Rama Gunta
Beilstein J. Org. Chem. 2015, 11, 1727–1731, doi:10.3762/bjoc.11.188
Graphical Abstract
Figure 1: RRM route to propellane derivatives and oxa-bowls.
Scheme 1: Synthesis of the oxa-bowl 1a via RRM.
Scheme 2: Synthesis of RRM products 1b and 5a starting from DA adduct 3b.
Scheme 3: Synthesis of the hexacyclic compound 1c using RRM.
Scheme 4: Synthesis of the propellane/oxa-bowl hybrids 7a,b via RRM.
Design and synthesis of hybrid cyclophanes containing thiophene and indole units via Grignard reaction, Fischer indolization and ring-closing metathesis as key steps
- Sambasivarao Kotha,
- Ajay Kumar Chinnam and
- Mukesh E. Shirbhate
Beilstein J. Org. Chem. 2015, 11, 1514–1519, doi:10.3762/bjoc.11.165
Graphical Abstract
Figure 1: Retrosynthetic approach to hybrid cyclophane derivative 1.
Scheme 1: Attempted synthesis of thiophenophane derivative 2.
Scheme 2: Synthesis of hybrid cyclophane 1.
Figure 2: The molecular crystal structure of 1 with 50% probability [41].
Scheme 3: Attempted synthesis of thiophenophane derivative 2a.
Scheme 4: Synthesis of cyclophane 1a with a thiophene and an indole moiety.
Synthesis of a tricyclic lactam via Beckmann rearrangement and ring-rearrangement metathesis as key steps
- Sambasivarao Kotha,
- Ongolu Ravikumar and
- Jadab Majhi
Beilstein J. Org. Chem. 2015, 11, 1503–1508, doi:10.3762/bjoc.11.163
Graphical Abstract
Figure 1: Retrosynthetic analysis of tricyclic amide 1.
Scheme 1: Synthesis of tricyclic ketone 4.
Scheme 2: Beckmann rearrangement of oximes 8a and 8b.
Scheme 3: Beckmann rearrangement reaction in a single step.
Scheme 4: Synthesis of ring-rearrangement precursors.
Scheme 5: Synthesis of Beckmann rearrangement precursors.
Scheme 6: Beckmann rearrangement of oxime isomers 11a and 11b.
Figure 2: Molecular crystal structure of compound 11b.
Scheme 7: Synthesis of aza tricyclic compound 1 by RRM.
Design and synthesis of polycyclic sulfones via Diels–Alder reaction and ring-rearrangement metathesis as key steps
- Sambasivarao Kotha and
- Rama Gunta
Beilstein J. Org. Chem. 2015, 11, 1373–1378, doi:10.3762/bjoc.11.148
Graphical Abstract
Figure 1: Retrosynthetic approach to polycyclic sulfones.
Scheme 1: Preparation of the sulfone 6 via oxidation.
Scheme 2: Synthesis of alkenylated sulfone derivatives.
Scheme 3: Synthesis of 10 by RRM of 2a.
Scheme 4: Synthesis of 1b using RRM.
Scheme 5: RRM of the dipentenyl sulfone 2c.
Scheme 6: RRM of the dihexenyl sulfone 2d.
Spiro annulation of cage polycycles via Grignard reaction and ring-closing metathesis as key steps
- Sambasivarao Kotha,
- Mohammad Saifuddin,
- Rashid Ali and
- Gaddamedi Sreevani
Beilstein J. Org. Chem. 2015, 11, 1367–1372, doi:10.3762/bjoc.11.147
Graphical Abstract
Figure 1: Structures of diverse biologically as well as theoretically interesting molecules.
Figure 2: Retrosynthetic analysis of bis-spiro-pyrano cage compound 7.
Scheme 1: Synthesis of hexacyclic cage dione 10.
Scheme 2: Synthesis of tetrahydrofuran-based cage compounds 12 and 13.
Figure 3: (a)Optimized structure of 12, (b) optimized structure of 13.
Scheme 3: Synthesis di-allyl cage compound 11.
Scheme 4: Synthesis of spiro-pyrano cage molecules 7 and 17.
Figure 4: (a) Optimized structure of 18, (b) optimized structure of 7.
Scheme 5: Synthesis of octacyclic cage compound 18 via intramolecular DA reaction.
Scheme 6: Attempted synthesis to cage compound 20.
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
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)...
Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps
- Sambasivarao Kotha and
- Ongolu Ravikumar
Beilstein J. Org. Chem. 2015, 11, 1259–1264, doi:10.3762/bjoc.11.140
Graphical Abstract
Figure 1: Commercially available ruthenium catalysts used in RRM metathesis.
Figure 2: Crystal structure of 5 with thermal ellipsoids drawn at 50% probability level.
Scheme 1: Synthesis of hexacyclic compound 6a by using an RRM approach.
Scheme 2: Synthesis of hexacyclic compound 11 by using an RRM route.
Hybrid macrocycle formation and spiro annulation on cis-syn-cis-tricyclo[6.3.0.02,6]undeca-3,11-dione and its congeners via ring-closing metathesis
- Sambasivarao Kotha,
- Ajay Kumar Chinnam and
- Rashid Ali
Beilstein J. Org. Chem. 2015, 11, 1123–1128, doi:10.3762/bjoc.11.126
Graphical Abstract
Figure 1: Natural and non-natural products containing quinane systems.
Figure 2: Quinane building blocks (1–3) and metathetic catalyst used in our strategy.
Scheme 1: Synthesis of tricyclic diones 5 and 2.
Figure 3: Retrosynthetic approach to aza-polyquinane 6 and spiro-polyquinane 7.
Scheme 2: Synthesis of the diindole derivative 9 Reagents and conditions: (i) TA:DMU, PhNHNH3Cl, 70 °C, 6 h, ...
Scheme 3: Synthesis of the macrocyclic aza-polyquinane derivative 6. Reagents and conditions: (i) NaH, allyl ...
Scheme 4: Synthesis of the spiro-polyquinane 7. Reagents and conditions: (i) NaH, allyl bromide, THF, rt, 24 ...
Scheme 5: General strategy to bis-spirocycles via RCM.
Design and synthesis of novel bis-annulated caged polycycles via ring-closing metathesis: pushpakenediol
- Sambasivarao Kotha and
- Mirtunjay Kumar Dipak
Beilstein J. Org. Chem. 2014, 10, 2664–2670, doi:10.3762/bjoc.10.280
Graphical Abstract
Figure 1: Selected theoretically interesting molecules.
Figure 2: Retrosynthetic approach toward bis-annulated PCUD.
Scheme 1: The synthesis of diallylated tricyclic diene 19.
Scheme 2: The synthesis of diallylated pentacyclic dione 20.
Scheme 3: The synthesis of heptacyclic diol 22.
Figure 3: (a) Optimized structure of 22 (b) Ancient flying machine “Pushpak Viman”.
Scheme 4: The synthesis of diallylated hexacyclic diols.
Scheme 5: The attempted synthesis of heptacyclic diol via ring-rearrangement metathesis.
Synthesis of indole-based propellane derivatives via Weiss–Cook condensation, Fischer indole cyclization, and ring-closing metathesis as key steps
- Sambasivarao Kotha,
- Ajay Kumar Chinnam and
- Arti Tiwari
Beilstein J. Org. Chem. 2013, 9, 2709–2714, doi:10.3762/bjoc.9.307
Graphical Abstract
Figure 1: [4.4.2] and [1.1.1]propellanes.
Figure 2: Alkaloids containing indole-based propellanes.
Figure 3: Retrosynthetic strategy to indole-based propellane 4.
Scheme 1: Preparation of diindole dione 2.
Scheme 2: Synthesis of allylated indole derivatives 3, 7 and 8.
Scheme 3: Synthesis of indole-based propellane derivatives 4 and 11 by RCM route.
Scheme 4: Synthesis of 4 by Weiss–Cook condensation and two fold Fischer indole cyclization.
