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Blangetti M, Fleming P, O’Shea DF. Homo- and Hetero-oxidative Coupling of Benzyl Anions. J Org Chem 2012; 77:2870-7. [DOI: 10.1021/jo3000805] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Marco Blangetti
- School of Chemistry and
Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Patricia Fleming
- School of Chemistry and
Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Donal F. O’Shea
- School of Chemistry and
Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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3
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Yamakoshi H, Ikarashi F, Minami M, Shibuya M, Sugahara T, Kanoh N, Ohori H, Shibata H, Iwabuchi Y. Syntheses of naturally occurring cytotoxic [7.7]paracyclophanes, (−)-cylindrocyclophane A and its enantiomer, and implications for biological activity. Org Biomol Chem 2009; 7:3772-81. [DOI: 10.1039/b909646a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Govender S, Mmutlane EM, van Otterlo WAL, de Koning CB. Bidirectional racemic synthesis of the biologically active quinone cardinalin 3. Org Biomol Chem 2007; 5:2433-40. [PMID: 17637963 DOI: 10.1039/b707187f] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Readily available 2,2',6,6'-tetramethoxy-1,1'-biphenyl was transformed in 14 synthetic steps into the natural product cardinalin 3 using a bidirectional approach. One of the key steps was the formation of the cis-1,3-dimethylnaphtho[2,3-c]pyran ring. (+/-)-1,1'-[6,6'-Diallyl-5,5'-bis(benzyloxy)-1,1',3,3'-tetramethoxy-2,2'-binaphthalene-7,7'-diyl]diethanol was treated with O(2) in the presence of CuCl(2) and catalytic PdCl(2) to afford 5,5'-bis(benzyloxy)-7,7',9,9'-tetramethoxy-1,1',3,3'-tetramethyl-1H,1'H-8,8'-bibenzo[g]isochromene. Hydrogenation of this compound afforded 7,7',9,9'-tetramethoxy-cis-1,3-cis-1',3'-tetramethyl-3,3',4,4'-tetrahydro-1H,1'H-8,8'-bibenzo[g]isochromene-5,5'-diol in quantitative yield, which was converted in 3 steps to cardinalin 3.
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Affiliation(s)
- Sameshnee Govender
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits 2050, South Africa
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D??browski M, Kurach P, Luliński S, Serwatowski J. Anortho-lithiated derivative of protected phenylboronic acid: an approach toortho-functionalized arylboronic acids and 1,3-dihydro-1-hydroxybenzo[c][2,1]oxaboroles. Appl Organomet Chem 2007. [DOI: 10.1002/aoc.1217] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Stolarzewicz A, Grobelny Z, Pisarski W, Łosiewicz B, Piekarnik B, Swinarew A. Photochemical, Electrochemical and Enzymatic Methods for Ether‐Bond Cleavage. European J Org Chem 2006. [DOI: 10.1002/ejoc.200500794] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Andrzej Stolarzewicz
- Institute of Materials Science, University of Silesia, 40‐007 Katowice, Poland, Fax: +48‐32‐259‐6929
| | - Zbigniew Grobelny
- Institute of Materials Science, University of Silesia, 40‐007 Katowice, Poland, Fax: +48‐32‐259‐6929
| | - Wojciech Pisarski
- Institute of Materials Science, University of Silesia, 40‐007 Katowice, Poland, Fax: +48‐32‐259‐6929
| | - Bożena Łosiewicz
- Institute of Materials Science, University of Silesia, 40‐007 Katowice, Poland, Fax: +48‐32‐259‐6929
| | - Beata Piekarnik
- Institute of Materials Science, University of Silesia, 40‐007 Katowice, Poland, Fax: +48‐32‐259‐6929
| | - Andrzej Swinarew
- Institute of Materials Science, University of Silesia, 40‐007 Katowice, Poland, Fax: +48‐32‐259‐6929
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Yus M, Foubelo F. Homologation of Heterocycles by a Sequential Reductive Opening Lithiation–Electrophilic Substitution–Cyclization. ADVANCES IN HETEROCYCLIC CHEMISTRY 2006. [DOI: 10.1016/s0065-2725(06)91002-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Grobelny Z. Chemical Methods for Ether‐Bond Cleavage by Electron‐Transfer Reagents. European J Org Chem 2004. [DOI: 10.1002/ejoc.200400004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Zbigniew Grobelny
- Institute of Materials Science, University of Silesia, 40‐007 Katowice, Poland, Fax: + 48‐32‐2596929
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Azzena U, Dettori G, Idini MV, Pisano L, Sechi G. Regioselective reductive demethoxylation of 3,4,5-trimethoxystilbenes. Tetrahedron 2003. [DOI: 10.1016/j.tet.2003.08.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Oxidative Aromatization of 2-Acylcyclohexane-1,3-dione Derivatives Using Iodine in Methanol. B KOREAN CHEM SOC 2003. [DOI: 10.5012/bkcs.2003.24.8.1057] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Azzena U, Vittoria Idini M, Pilo L. Synthesis of Antibiotic Stilbenes by Reductive Metalation of 3,4,5-Trimethoxybenzaldehyde Dimethyl Acetal. SYNTHETIC COMMUN 2003. [DOI: 10.1081/scc-120018690] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Reductive lithiation of cyclic benzofused ethers: a source of oxygen-functionalised organolithium compounds. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00434-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pisano L, Farriol M, Asensio X, Gallardo I, González-Lafont A, Lluch JM, Marquet J. Thermodynamics, kinetics, and dynamics of the two alternative aniomesolytic fragmentations of C-O bonds: an electrochemical and theoretical study. J Am Chem Soc 2002; 124:4708-15. [PMID: 11971720 DOI: 10.1021/ja012444g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fragmentation reactions of radical anions (mesolytic cleavages) of cyanobenzyl alkyl ethers (intramolecular dissociative electron transfer, heterolytic cleavages) have been studied electrochemically. The intrinsic barriers for the processes have been established from the experimental thermodynamic and kinetic parameters. These values are more than 3 kcal/mol lower as an average than the related homolytic mesolytic fragmentations of radical anions of 4-cyanophenyl ethers. In the particular case of isomers 4-cyanobenzyl phenyl ether and 4-cyanophenyl benzyl ether, the difference in intrinsic barriers amounts to 5.5 kcal/mol, and this produces an energetic crossing where the thermodynamically more favorable process (homolytic) is the kinetically slower one. The fundamental reasons for this behavior have been established by means of theoretical calculations within the density functional theory framework, showing that, in this case, the factors that determine the kinetics are clearly different (mainly present in the transition state) from those that determine the thermodynamics and they are not related to the regioconservation of the spin density ("spin regioconservation principle"). Our theoretical results reproduce quite well the experimental energetic difference of barriers and demonstrate the main structural origin of the difference.
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Affiliation(s)
- Luisa Pisano
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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Gissot A, Becht JM, Desmurs JR, Pévère V, Wagner A, Mioskowski C. Directedortho-Metalation, a New Insight into Organosodium Chemistry. Angew Chem Int Ed Engl 2002. [DOI: 10.1002/1521-3757(20020118)114:2<350::aid-ange350>3.0.co;2-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Electrostatic and electrophilic catalysis in the reductive cleavage of alkyl aryl ethers. The influence of ion pairing on the regioselectivity. J Org Chem 2000; 65:322-31. [PMID: 10813937 DOI: 10.1021/jo991059v] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrophilic and electrostatic catalysis have been identified as distinct contributions that affect the reactivity of radical anions in the reductive cleavage of alkyl aryl ethers. Two modes of mesolytic scission of these radical anions are possible: homolytic (dealkylation, a thermodynamically favored but kinetically forbidden process) and heterolytic (dealkoxylation). From our studies (alkali metal reductions, electrochemical studies, use of substrates with a preformed positive charge in certain positions of their structure) it can be concluded that the heterolytic scission is very much dependent on the electrophilic assistance by the counterion and it is only observed in contact ionic pairs with unsaturated cations (electrophilic catalysis). On the other hand, the homolytic scission is observed in solvent-separated ionic pairs, and it is especially efficient when the pair has a controlled topology with a tetralkylammonium cation (saturated cation) near the oxygen atom. The effect of the cation has, in this case, electrostatic origin (electrostatic catalysis), probably lowering the barrier of the intramolecular pi-sigma electron transfer process and thus reducing the kinetic control of the reaction in such a way that the thermodynamically more favorable process is produced.
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Single electron transfer reductive cleavage of the aryl-nitrogen bond in phenyl-substituted dimethylanilines. Tetrahedron Lett 1999. [DOI: 10.1016/s0040-4039(99)01758-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wada M, Konishi H, Kai T, Takeuchi H, Natsume S, Erabi T. Reactions of Bis(2,6-dimethoxyphenyl)methanol in Common Organic Solvents in the Presence of an Acid. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1998. [DOI: 10.1246/bcsj.71.1667] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kadam SM, Nayak SK, Banerji A. Dramatic Influence of Nitrogen Heterocycles on the Activity of Low-Valent Titanium Reagent: An Improved One-Pot Synthesis of Phenanthrenes. SYNTHETIC COMMUN 1995. [DOI: 10.1080/00397919508010799] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Wada M, Wakamori H, Hiraiwa A, Erabi T. Selective Preparation of 1-Halo-2,6-dimethoxybenzenes from Bis(2,6-dimethoxyphenyl)dimethyltin. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1992. [DOI: 10.1246/bcsj.65.1389] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kotnis AS. A convenient, practical synthesis of substituted resorcinols: synthesis of DB-2073 and olivetol. Tetrahedron Lett 1991. [DOI: 10.1016/0040-4039(91)80801-c] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Banerji A, Nayak SK. Unprecedented reductive dealkoxylation of aryl alkyl ethers and intramolecular C–C coupling of 2,2′-dialkoxystilbenes with low valent titanium: one-pot synthesis of phenanthrenes. ACTA ACUST UNITED AC 1991. [DOI: 10.1039/c39910001432] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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