Wikipedia

Cobalt(II)–porphyrin catalysis

Cobalt(II)–porphyrin catalysis is a process in which a Co(II) porphyrin complex acts as a catalyst, inducing and accelerating a chemical reaction.

It is a compound in organic chemistry and free radical reactions that can involve homolysis. It is a one-electron catalytic approach for homolytic radical chemistry[1] based on structurally well-defined Co(II) complexes.[2] Due to their distinctive radical mechanisms that involve metal-stabilized radical intermediates, such as α-metalloalkyl radicals, α-metalloaminyl radicals, and α-metalloxyl radicals, the Co(II)–porphyrin-based catalysis system addresses some long-standing challenges in organic transformations.[3][4]

A family of unique D2-symmetric chiral porphyrins are effective in a range of stereodefined transformations.[5]

Attributes

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Co(II)–porphyrin catalysts have good thermal and metal coordination stability resulting from the macrocyclic chelation effect of the aromatic ligand. Once inserted into the macrocyclic ring, dissociation of the metal ion is exceedingly difficult, under most reaction conditions, leading to increased catalyst lifetime . Metal ion contamination is a practical issue for many metal-catalyzed processes, and is especially important for pharmaceutical application.

Co(II)–porphyrin catalysts lack vacant cis-coordination sites available (all occupied). This unique metal coordination mode can prevent a number of possible side reactions associated with cis-coordination, and results in a more effective and selective catalytic process. Although cis-coordination is requisite for many catalytic processes, it is not required for catalytic cyclopropanation or aziridination, or for atom or group transfer reactions.

Third, it has been well documented that the physical and chemical properties of a porphyrin complex of a given metal ion can be systematically tuned by introducing peripheral substituents with varied electronic, steric, and conformational environments on the aromatic ring structure of the porphyrin ligand. X. Peter Zhang's group have accomplished porphyrin modification by using palladium-catalyzed coupling processes of chiral amides on bromoporphyrin templates.

 

Together, these advantages provide Co(II)–porphyrin catalysts with high catalytic selectivities and turnover numbers.[6]

Application

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Radical carbenes such as Co–porphyrin catalysis activate diazo reagents and organic azides to generate C- and N-centered radicals, respectively, with nitrogen as the only byproduct in a controlled and catalytic manner. The initially formed C- and N-centered radicals can undergo common radical reactions such as radical addition and atom abstraction, but with effective control of reactivity and stereoselectivity by the porphyrin ligand environment.[7][8][9][10][11][12][13][14][15][16][17][18]

 
 

References

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  1. ^ Studer, Armido; Curran, Dennis P. (2016-01-04). "Catalysis of Radical Reactions: A Radical Chemistry Perspective". Angewandte Chemie International Edition. 55 (1): 58–102. doi:10.1002/anie.201505090. ISSN 1521-3773. PMID 26459814. S2CID 20122229.
  2. ^ Cornils, Boy; Herrmann, Wolfgang A.; Beller, Matthias; Paciello, Rocco (2017-12-26). Applied Homogeneous Catalysis with Organometallic Compounds: A Comprehensive Handbook in Four Volumes. John Wiley & Sons. ISBN 978-3-527-32897-0.
  3. ^ Degennaro, Leonardo; Trinchera, Piera; Luisi, Renzo (2014-08-27). "Recent Advances in the Stereoselective Synthesis of Aziridines". Chemical Reviews. 114 (16): 7881–7929. doi:10.1021/cr400553c. ISSN 0009-2665. PMID 24823261.
  4. ^ Pellissier, Hélène; Clavier, Hervé (2014-03-12). "Enantioselective Cobalt-Catalyzed Transformations". Chemical Reviews. 114 (5): 2775–2823. doi:10.1021/cr4004055. ISSN 0009-2665. PMID 24428605.
  5. ^ Doyle, Michael P. (2009-01-19). "Exceptional Selectivity in Cyclopropanation Reactions Catalyzed by Chiral Cobalt(II)–Porphyrin Catalysts". Angewandte Chemie International Edition. 48 (5): 850–852. doi:10.1002/anie.200804940. ISSN 1521-3773. PMC 3517106. PMID 19117005.
  6. ^ Lu, Hongjian; Zhang, X. Peter (2011-03-21). "Catalytic C–H functionalization by metalloporphyrins: recent developments and future directions". Chemical Society Reviews. 40 (4): 1899–1909. doi:10.1039/C0CS00070A. ISSN 1460-4744. PMID 21088785.
  7. ^ Lu, Hongjian; Dzik, Wojciech I.; Xu, Xue; Wojtas, Lukasz; de Bruin, Bas; Zhang, X. Peter (2011-06-08). "Experimental Evidence for Cobalt(III)-Carbene Radicals: Key Intermediates in Cobalt(II)-Based Metalloradical Cyclopropanation". Journal of the American Chemical Society. 133 (22): 8518–8521. doi:10.1021/ja203434c. ISSN 0002-7863. PMID 21563829.
  8. ^ Belof, Jonathan L.; Cioce, Christian R.; Xu, Xue; Zhang, X. Peter; Space, Brian; Woodcock, H. Lee (2011-05-23). "Characterization of Tunable Radical Metal–Carbenes: Key Intermediates in Catalytic Cyclopropanation". Organometallics. 30 (10): 2739–2746. doi:10.1021/om2001348. ISSN 0276-7333. PMC 3105361. PMID 21643517.
  9. ^ Dzik, Wojciech I.; Xu, Xue; Zhang, X. Peter; Reek, Joost N. H.; de Bruin, Bas (2010-08-11). "'Carbene Radicals' in CoII(por)-Catalyzed Olefin Cyclopropanation". Journal of the American Chemical Society. 132 (31): 10891–10902. doi:10.1021/ja103768r. ISSN 0002-7863. PMID 20681723.
  10. ^ Wang, Yong; Wen, Xin; Cui, Xin; Wojtas, Lukasz; Zhang, X. Peter (2017-01-25). "Asymmetric Radical Cyclopropanation of Alkenes with In Situ-Generated Donor-Substituted Diazo Reagents via Co(II)-Based Metalloradical Catalysis". Journal of the American Chemical Society. 139 (3): 1049–1052. doi:10.1021/jacs.6b11336. ISSN 0002-7863. PMC 5266645. PMID 28051870.
  11. ^ Xu, Xue; Zhu, Shifa; Cui, Xin; Wojtas, Lukasz; Zhang, X. Peter (2013-11-04). "Cobalt(II)-Catalyzed Asymmetric Olefin Cyclopropanation with α-Ketodiazoacetates". Angewandte Chemie International Edition. 52 (45): 11857–11861. doi:10.1002/anie.201305883. ISSN 1521-3773. PMC 3943748. PMID 24115575.
  12. ^ Xu, Xue; Lu, Hongjian; Ruppel, Joshua V.; Cui, Xin; Lopez de Mesa, Silke; Wojtas, Lukasz; Zhang, X. Peter (2011-10-05). "Highly Asymmetric Intramolecular Cyclopropanation of Acceptor-Substituted Diazoacetates by Co(II)-Based Metalloradical Catalysis: Iterative Approach for Development of New-Generation Catalysts". Journal of the American Chemical Society. 133 (39): 15292–15295. doi:10.1021/ja2062506. ISSN 0002-7863. PMID 21870825.
  13. ^ Zhu, Shifa; Xu, Xue; Perman, Jason A.; Zhang, X. Peter (2010-09-22). "A General and Efficient Cobalt(II)-Based Catalytic System for Highly Stereoselective Cyclopropanation of Alkenes with α-Cyanodiazoacetates". Journal of the American Chemical Society. 132 (37): 12796–12799. doi:10.1021/ja1056246. ISSN 0002-7863. PMID 20735129.
  14. ^ Zhu, Shifa; Perman, Jason A.; Zhang, X. Peter (2008-10-20). "Acceptor/Acceptor-Substituted Diazo Reagents for Carbene Transfers: Cobalt-Catalyzed Asymmetric Z-Cyclopropanation of Alkenes with α-Nitrodiazoacetates". Angewandte Chemie International Edition. 47 (44): 8460–8463. doi:10.1002/anie.200803857. ISSN 1521-3773. PMID 18825766.
  15. ^ Zhu, Shifa; Ruppel, Joshua V.; Lu, Hongjian; Wojtas, Lukasz; Zhang, X. Peter (2008-04-01). "Cobalt-Catalyzed Asymmetric Cyclopropanation with Diazosulfones: Rigidification and Polarization of Ligand Chiral Environment via Hydrogen Bonding and Cyclization". Journal of the American Chemical Society. 130 (15): 5042–5043. doi:10.1021/ja7106838. ISSN 0002-7863. PMID 18357991.
  16. ^ Chen, Ying; Ruppel, Joshua V.; Zhang, X. Peter (2007-10-01). "Cobalt-Catalyzed Asymmetric Cyclopropanation of Electron-Deficient Olefins". Journal of the American Chemical Society. 129 (40): 12074–12075. doi:10.1021/ja074613o. ISSN 0002-7863. PMID 17877352.
  17. ^ Cui, Xin; Xu, Xue; Wojtas, Lukasz; Kim, Martin M.; Zhang, X. Peter (2012-12-12). "Regioselective Synthesis of Multisubstituted Furans via Metalloradical Cyclization of Alkynes with α-Diazocarbonyls: Construction of Functionalized α-Oligofurans". Journal of the American Chemical Society. 134 (49): 19981–19984. doi:10.1021/ja309446n. ISSN 0002-7863. PMC 3531582. PMID 23205846.
  18. ^ Cui, Xin; Xu, Xue; Lu, Hongjian; Zhu, Shifa; Wojtas, Lukasz; Zhang*, X. Peter (2011-03-16). "Enantioselective Cyclopropenation of Alkynes with Acceptor/Acceptor-Substituted Diazo Reagents via Co(II)-Based Metalloradical Catalysis". Journal of the American Chemical Society. 133 (10): 3304–3307. doi:10.1021/ja111334j. ISSN 0002-7863. PMID 21332140.
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