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Gu ZY, Cao JJ, Wang SY, Ji SJ. The involvement of the trisulfur radical anion in electron-catalyzed sulfur insertion reactions: facile synthesis of benzothiazine derivatives under transition metal-free conditions. Chem Sci 2016; 7:4067-4072. [PMID: 30155050 PMCID: PMC6013918 DOI: 10.1039/c6sc00240d] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/03/2016] [Indexed: 11/21/2022] Open
Abstract
An efficient and practical synthesis of benzothiazine by K2S initiated sulfur insertion reaction with enaminones via electron catalysis is developed. This protocol provides a new, environment-friendly and simple strategy to construct benzothiazine derivatives via formation of two C-S bonds under transition metal-free, additive-free and oxidant-free conditions. K2S not only provides the sulfur insertion source, but also ignites the reaction through the formation of a trisulfur radical anion and electrons in DMF.
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Affiliation(s)
- Zheng-Yang Gu
- Key Laboratory of Organic Synthesis of Jiangsu Province , College of Chemistry , Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology , Soochow University , Suzhou 215123 , China . ;
| | - Jia-Jia Cao
- Key Laboratory of Organic Synthesis of Jiangsu Province , College of Chemistry , Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology , Soochow University , Suzhou 215123 , China . ;
| | - Shun-Yi Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province , College of Chemistry , Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology , Soochow University , Suzhou 215123 , China . ;
| | - Shun-Jun Ji
- Key Laboratory of Organic Synthesis of Jiangsu Province , College of Chemistry , Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology , Soochow University , Suzhou 215123 , China . ;
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Mohamed RK, Mondal S, Jorner K, Delgado TF, Lobodin VV, Ottosson H, Alabugin IV. The Missing C1-C5 Cycloaromatization Reaction: Triplet State Antiaromaticity Relief and Self-Terminating Photorelease of Formaldehyde for Synthesis of Fulvenes from Enynes. J Am Chem Soc 2015; 137:15441-50. [PMID: 26536479 DOI: 10.1021/jacs.5b07448] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The last missing example of the four archetypical cycloaromatizations of enediynes and enynes was discovered by combining a twisted alkene excited state with a new self-terminating path for intramolecular conversion of diradicals into closed-shell products. Photoexcitation of aromatic enynes to a twisted alkene triplet state creates a unique stereoelectronic situation, which is facilitated by the relief of excited state antiaromaticity of the benzene ring. This enables the usually unfavorable 5-endo-trig cyclization and merges it with 5-exo-dig closure. The 1,4-diradical product of the C1-C5 cyclization undergoes internal H atom transfer that is coupled with the fragmentation of an exocyclic C-C bond. This sequence provides efficient access to benzofulvenes from enynes and expands the utility of self-terminating aromatizing enyne cascades to photochemical reactions. The key feature of this self-terminating reaction is that, despite the involvement of radical species in the key cyclization step, no external radical sources or quenchers are needed to provide the products. In these cascades, both radical centers are formed transiently and converted to the closed-shell products via intramolecular H-transfer and C-C bond fragmentation. Furthermore, incorporating C-C bond cleavage into the photochemical self-terminating cyclizations of enynes opens a new way for the use of alkenes as alkyne equivalents in organic synthesis.
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Affiliation(s)
| | | | - Kjell Jorner
- Department of Chemistry - BMC, Uppsala University , Box 576, 751 23 Uppsala, Sweden
| | | | - Vladislav V Lobodin
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States.,Future Fuels Institute, Florida State University , Tallahassee, Florida 32310, United States
| | - Henrik Ottosson
- Department of Chemistry - BMC, Uppsala University , Box 576, 751 23 Uppsala, Sweden
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Pan XQ, Zou JP, Yi WB, Zhang W. Recent advances in sulfur- and phosphorous-centered radical reactions for the formation of S–C and P–C bonds. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.04.117] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Mohamed RK, Mondal S, Gold B, Evoniuk CJ, Banerjee T, Hanson K, Alabugin IV. Alkenes as Alkyne Equivalents in Radical Cascades Terminated by Fragmentations: Overcoming Stereoelectronic Restrictions on Ring Expansions for the Preparation of Expanded Polyaromatics. J Am Chem Soc 2015; 137:6335-49. [DOI: 10.1021/jacs.5b02373] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Rana K. Mohamed
- Florida State University, Tallahassee, Florida 32306, United States
| | - Sayantan Mondal
- Florida State University, Tallahassee, Florida 32306, United States
| | - Brian Gold
- Florida State University, Tallahassee, Florida 32306, United States
| | | | - Tanmay Banerjee
- Florida State University, Tallahassee, Florida 32306, United States
| | - Kenneth Hanson
- Florida State University, Tallahassee, Florida 32306, United States
| | - Igor V. Alabugin
- Florida State University, Tallahassee, Florida 32306, United States
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Novel radical tandem 1,6-enynes thioacylation/cyclization: Au–Pd nanoparticles catalysis versus thermal activation as a function of the substrate specificity. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.10.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zhang G, Yi H, Chen H, Bian C, Liu C, Lei A. Trisulfur Radical Anion as the Key Intermediate for the Synthesis of Thiophene via the Interaction between Elemental Sulfur and NaOtBu. Org Lett 2014; 16:6156-9. [DOI: 10.1021/ol503015b] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Guoting Zhang
- College
of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Hong Yi
- College
of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Hong Chen
- College
of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Changliang Bian
- College
of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Chao Liu
- College
of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Aiwen Lei
- College
of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China
- National
Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, Jiangxi, P. R. China
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7
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Affiliation(s)
- Fabrice Dénès
- Laboratoire CEISAM UMR CNRS 6230 - UFR des Sciences et Techniques, Université de Nantes , 2 rue de la Houssinière, BP 92208 - 44322 Nantes Cedex 3, France
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8
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Wille U. Radical Cascades Initiated by Intermolecular Radical Addition to Alkynes and Related Triple Bond Systems. Chem Rev 2012; 113:813-53. [DOI: 10.1021/cr100359d] [Citation(s) in RCA: 465] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Uta Wille
- School of Chemistry and
BIO21 Molecular Science and
Biotechnology Institute, Australian Research Council Centre of Excellence
for Free Radical Chemistry and Biotechnology, The University of Melbourne, 30 Flemington Road, Parkville, Victoria
3010, Australia
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