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Begum S, Bhattacharya R, Paul S, Chakraborty TK. Cp 2TiCl-Promoted Endo-Trig Radical Cyclization to Six- and Seven-Membered Carbocycles: Synthesis of (±)-Isoclavukerin A. J Org Chem 2023; 88:12677-12697. [PMID: 37608565 DOI: 10.1021/acs.joc.3c01356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
A systematic study is undertaken to investigate the less explored endo-trig radical cyclization in activated olefin-appended epoxides using Cp2TiCl. The radical generated by the Ti(III)-promoted reductive opening of the epoxy ring promptly underwent endo-trig cyclization, giving access to differently 1,3-disubstituted six- and seven-membered carbocycles in good yields and diastereoselectivity. This protocol was successfully employed in the construction of 5,7- and 6,7-fused bicyclic frameworks entailing a de novo synthesis of (±)-isoclavukerin A belonging to tri-nor-guaiane class of sesquiterpene natural products in eight simple steps from commercially available starting materials. Besides the Ti(III)-mediated reaction serving as a key step in the synthesis, a sequential [2,3]-sigmatropic rearrangement/syn-elimination of an allyl sulfenate intermediate successfully rendered the highly constrained diene moiety in the hydroazulene core of the target molecule.
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Affiliation(s)
- Sabnam Begum
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru 560012, India
| | - Rajarshi Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru 560012, India
| | - Shashwati Paul
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru 560012, India
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Singh VK, Chakraborty TK. Total Synthesis of Panaginsene. Chem Asian J 2021; 16:753-756. [PMID: 33638240 DOI: 10.1002/asia.202100144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/26/2021] [Indexed: 11/10/2022]
Abstract
The total synthesis of panaginsene has been accomplished in 11 linear steps starting from methyl 3,3-dimethyl-5-oxocyclopent-1-ene-1-carboxylate. The key steps are a Sharpless asymmetric epoxidation and Ti(III)-mediated reductive epoxide opening-radical cyclization to construct the chiral quaternary carbon stereocenter followed by a very challenging HWE olefination reaction on an 1,3-keto aldehyde and a late stage McMurry olefination using low valent titanium to construct the highly constrained angular tetrasubstituted olefin in a five-membered ring.
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Affiliation(s)
- Vipin Kumar Singh
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru, 560012, India
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Nallasivam JL, Chakraborty TK. Titanocene(III)-Mediated 5-exo-trig Radical Cyclization: En Route to Spirooxindole-Based Tetrahydrofuran and Bicyclic Lactone. J Org Chem 2019; 84:16124-16138. [PMID: 31793298 DOI: 10.1021/acs.joc.9b02608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The isatin core system is of immense importance due to the highly reactive prochiral C-3 position, which paves an easy way to construct large arrays of spirooxindole heterocyclic motifs. Herein, we depict an isatin-derived and 3,3'-disubstituted oxindole-appended epoxy-acrylate undergoing Cp2Ti(III)Cl-mediated reductive oxirane-ring opening with concomitant intramolecular 5-exo-trig radical cyclization leading to tetrahydrofuran-based oxa-spirooxindole systems. The fused spirooxindole structural feature is embedded in many natural products and tends to exhibit a wide spectrum of biological activities. The presence of more than one quaternary center and the availability of multiple functional groups like hydroxyl, ester, or lactone in the resultant products expand the scope of synthetic applications of the newly acquired oxa-spirooxindole molecules.
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Klare S, Gordon JP, Gansäuer A, RajanBabu TV, Nugent WA. The Reaction of β,γ-Epoxy Alcohols with Titanium(III) Reagents. A Proposed Role for Intramolecular Hydrogen Bonding. Tetrahedron 2019; 75:130662. [PMID: 32601512 PMCID: PMC7322769 DOI: 10.1016/j.tet.2019.130662] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Sven Klare
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straβe 1, 53121 Bonn, Germany
| | - Jonathan P. Gordon
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210 USA
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straβe 1, 53121 Bonn, Germany
| | - T. V. RajanBabu
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210 USA
| | - William A. Nugent
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210 USA
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Das D, Chakraborty TK. An overview of the recent synthetic studies toward penifulvins and other fenestranes. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Singh N, Pulukuri KK, Chakraborty TK. Formal synthesis of degraded sterol (+)-aplykurodinone-1. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.05.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Mukherjee S, Roy R, Chandra Roy S. Titanocene(III) Chloride Mediated Stereoselective Synthesis of Trisubstituted Tetrahydrofurans and a Spirolactone by Tandem Radical Reactions. European J Org Chem 2014. [DOI: 10.1002/ejoc.201400097] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Morcillo SP, Miguel D, Campaña AG, Álvarez de Cienfuegos L, Justicia J, Cuerva JM. Recent applications of Cp2TiCl in natural product synthesis. Org Chem Front 2014. [DOI: 10.1039/c3qo00024a] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Titanocene(iii)-based approaches have been demonstrated to be useful in the straightforward syntheses of many natural products from readily available starting materials.
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Affiliation(s)
- Sara P. Morcillo
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | - Delia Miguel
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | - Araceli G. Campaña
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | | | - José Justicia
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | - Juan M. Cuerva
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
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Basu S, Kandiyal PS, Ampapathi RS, Chakraborty TK. Ti(iii)-mediated radical cyclization of epoxy-β-aminoacrylate in the synthesis of the substituted pyrrolidine core of necine bases: synthesis of 2-epi-rosmarinecine. RSC Adv 2013. [DOI: 10.1039/c3ra42315h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Gharpure SJ, Niranjana P, Porwal SK. Stereoselective Synthesis of Oxa- and Aza-Angular Triquinanes Using Tandem Radical Cyclization to Vinylogous Carbonates and Carbamates. Org Lett 2012; 14:5476-9. [DOI: 10.1021/ol302557a] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Santosh J. Gharpure
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India, and Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - P. Niranjana
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India, and Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suheel K. Porwal
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India, and Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Stereoselective synthesis of 2,3-disubstituted dihydrobenzofuran using alkyne Prins type cyclization to vinylogous carbonates. J CHEM SCI 2011. [DOI: 10.1007/s12039-011-0162-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Sreekanth M, Pranitha G, Jagadeesh B, Chakraborty TK. Ti(III)-mediated opening of 2,3-epoxy alcohols to build five-membered carbocycles with multiple chiral centres. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gharpure SJ, Porwal SK. Alkyl radical cyclization to vinylogous carbonates for the stereoselective synthesis of unsymmetrical dioxa-cage compounds: effect of conformation on the rate of cyclization versus reduction. Tetrahedron 2011. [DOI: 10.1016/j.tet.2010.11.098] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gharpure SJ, Sathiyanarayanan AM. Stereoselective synthesis of oxazino[4,3-a]indoles employing the oxa-Pictet–Spengler reaction of indoles bearing N-tethered vinylogous carbonate. Chem Commun (Camb) 2011; 47:3625-7. [DOI: 10.1039/c0cc05558a] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gharpure SJ, Reddy SRB. Tandem SN2-Michael addition to vinylogous carbonates for the stereoselective construction of 2,3,3,5-tetrasubstituted tetrahydrofurans. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.09.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Stereoselective construction of quaternary chiral centers using Ti(III)-mediated opening of 2,3-epoxy alcohols: studies directed toward the synthesis of penifulvins. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.06.076] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Gharpure SJ, Shukla MK, Vijayasree U. Stereoselective Synthesis of Donor−Acceptor Substituted Cyclopropafuranones by Intramolecular Cyclopropanation of Vinylogous Carbonates: Divergent Synthesis of Tetrahydrofuran-3-one, Tetrahydropyran-3-one, and Lactones. Org Lett 2009; 11:5466-9. [DOI: 10.1021/ol902301h] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Santosh J. Gharpure
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - Manoj K. Shukla
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - U. Vijayasree
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
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A radical mediated approach to the stereoselective formal total synthesis of (+)-Sch 642305. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.06.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Chakraborty TK, Samanta R, Roy S, Sridhar B. Ti(III)-mediated radical cyclization of β-aminoacrylate containing epoxy alcohol moieties: synthesis of highly substituted azacycles. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.02.063] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Gharpure SJ, Reddy SRB. Tandem Alkylation−Michael Addition to Vinylogous Carbonates for the Stereoselective Construction of 2,3,3,6-Tetrasubstituted Tetrahydropyrans. Org Lett 2009; 11:2519-22. [DOI: 10.1021/ol900721q] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Santosh J. Gharpure
- Department of Chemistry, Indian Institute of Technology Madras, Chennai - 600036, India
| | - S. Raja Bhushan Reddy
- Department of Chemistry, Indian Institute of Technology Madras, Chennai - 600036, India
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Bergmeier SC, Lapinsky DJ. Chapter 3: Three-membered ring systems. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s0959-6380(09)70007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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Thiery E, Le Bras J, Muzart J. Reactivity versus Stability of Oxiranes under Palladium‐Catalyzed Reductive Conditions. European J Org Chem 2008. [DOI: 10.1002/ejoc.200800739] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Emilie Thiery
- Institut de Chimie Moléculaire de Reims, UMR 6229, CNRS – Université de Reims Champagne‐Ardenne, B. P. 1039, 51687 Reims Cedex 2, France, Fax: +33‐3‐26913166
| | - Jean Le Bras
- Institut de Chimie Moléculaire de Reims, UMR 6229, CNRS – Université de Reims Champagne‐Ardenne, B. P. 1039, 51687 Reims Cedex 2, France, Fax: +33‐3‐26913166
| | - Jacques Muzart
- Institut de Chimie Moléculaire de Reims, UMR 6229, CNRS – Université de Reims Champagne‐Ardenne, B. P. 1039, 51687 Reims Cedex 2, France, Fax: +33‐3‐26913166
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