1
|
Frolov AI, Chuchvera YO, Ostapchuk EN, Druzhenko TV, Volochnyuk DM, Ryabukhin SV. Toward a Chemical Constructor: A Lego-Like Approach for Formal α-Alkylation of Cyclic Ketones. J Org Chem 2024. [PMID: 38764429 DOI: 10.1021/acs.joc.3c02628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
A conceptual strategy for a formal α-alkylation of α-methylene ketones was developed. Diverse 1° and 2° alkyl substituents were generated in the α-position of various ketones via synthesis of enaminone (step 1) and treatment with organomagnesium (step 2) with subsequent catalytic hydrogenation (step 3, 1° alkyl) or organocopper reagents (step 4, 2° alkyl). Tolerance toward ester, Boc-protected amine, and α-fluoro-substituted ketone moieties was demonstrated. The suitability of the method for late-stage natural product modification was shown.
Collapse
Affiliation(s)
- Andriy I Frolov
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
| | | | - Eugeniy N Ostapchuk
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
| | - Tetiana V Druzhenko
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
| | - Dmytro M Volochnyuk
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 5 Akademik Kuhar Street, 02660 Kyiv, Ukraine
| | - Serhiy V Ryabukhin
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 5 Akademik Kuhar Street, 02660 Kyiv, Ukraine
| |
Collapse
|
2
|
Sennari G, Yamagishi H, Sarpong R. Remote C-H Amination and Alkylation of Camphor at C8 through Hydrogen-Atom Abstraction. J Am Chem Soc 2024; 146:7850-7857. [PMID: 38447162 DOI: 10.1021/jacs.4c01351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Camphor continues to serve as a versatile chiral building block for chemical synthesis. We have developed a novel method to functionalize the camphor skeleton at C8 using an intramolecular hydrogen atom abstraction. The key advance involves the use of a camphor-derived aminonitrile, which is converted to the corresponding nitrogen-centered radical under photoredox conditions to effect the 1,5-hydrogen atom transfer at C8. The resulting carbon-centered radical at C8 was utilized in a C-H amination to access topologically complex proline derivatives. Furthermore, the total synthesis of several sesquiterpenoids was accomplished by engaging the radical generated at C8 in alkylation reactions.
Collapse
Affiliation(s)
- Goh Sennari
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- O̅mura Satoshi Memorial Institute and Graduate School of Infection Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Hiroki Yamagishi
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| |
Collapse
|
3
|
Yamashita Y, Ogasawara Y, Banik T, Kobayashi S. Photoinduced Efficient Catalytic α-Alkylation Reactions of Active Methylene and Methine Compounds with Nonactivated Alkenes. J Am Chem Soc 2023; 145:23160-23166. [PMID: 37846890 PMCID: PMC10603815 DOI: 10.1021/jacs.3c07436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Indexed: 10/18/2023]
Abstract
In catalytic α-alkylation reactions of carbonyl compounds, although SN2-type substitution reactions of enolates with alkyl halides are a conventional methodology, addition reactions with alkenes are more desirable because of their atom-economical character; however, reactions with nonactivated alkenes are challenging. Here, we developed highly efficient catalytic α-alkylation reactions of active methylene and methine compounds with nonactivated alkenes such as 1-decene using an organophotocatalyst and lithium thiophenoxide as a Lewis acid/Brønsted base/hydrogen atom transfer (HAT) multifunctional catalyst under blue-light irradiation. The reaction was also performed with a higher degree of efficiency under a continuous-flow system to obtain the products in multigram scales. The present reaction system enables highly efficient and practical α-alkylation reactions of active methylene and methine compounds to be achieved.
Collapse
Affiliation(s)
- Yasuhiro Yamashita
- Department
of Chemistry, School of Science, The University
of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yoshihiro Ogasawara
- Department
of Chemistry, School of Science, The University
of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Trisha Banik
- Department
of Chemistry, School of Science, The University
of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shu̅ Kobayashi
- Department
of Chemistry, School of Science, The University
of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| |
Collapse
|
4
|
Wang P, Bay AV, Farnam EJ, Scheidt KA. Photocatalyzed Direct α-Alkylation of Esters Using Styrenes. Adv Synth Catal 2023; 365:2361-2366. [PMID: 38464363 PMCID: PMC10923595 DOI: 10.1002/adsc.202300253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Indexed: 03/12/2024]
Abstract
A mild photocatalyzed approach to achieve the α-alkylation of esters via formation of an α -radical is disclosed here. Cesium enolates of esters were generated in situ using Cs2CO3 as a base. A subsequent photocatalyzed oxidation at the α-carbon of these enolates produced an α-radical that was added into activated alkenes. This is the first example accessing the α-carbon radical of esters in photoredox catalyed transformations.
Collapse
Affiliation(s)
- Pengzhi Wang
- Department of Chemistry, Northwestern University, Silverman Hall, Evanston, Illinois 60208 USA
| | - Anna V Bay
- Department of Chemistry, Northwestern University, Silverman Hall, Evanston, Illinois 60208 USA
| | - Emelia J Farnam
- Department of Chemistry, Northwestern University, Silverman Hall, Evanston, Illinois 60208 USA
| | - Karl A Scheidt
- Department of Chemistry, Northwestern University, Silverman Hall, Evanston, Illinois 60208 USA
| |
Collapse
|
5
|
Luo MJ, Xiao Q, Li JH. Electro-/photocatalytic alkene-derived radical cation chemistry: recent advances in synthetic applications. Chem Soc Rev 2022; 51:7206-7237. [PMID: 35880555 DOI: 10.1039/d2cs00013j] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alkene-derived radical cations are versatile reactive intermediates and have been widely applied in the construction of complex functionalized molecules and cyclic systems for chemical synthesis. Therefore, the synthetic application of these alkene-derived radical cations represents a powerful and green tool that can be used to achieve the functionalization of alkenes partially because the necessity of stoichiometric external chemical oxidants and/or hazardous reaction conditions is eliminated. This review summarizes the recent advances in the synthetic applications of the electro-/photochemical alkene-derived radical cations, emphasizing the key single-electron oxidation steps of the alkenes, the scope and limitations of the substrates, and the related reaction mechanisms. Using electrocatalysis and/or photocatalysis, single electron transfer (SET) oxidation of the CC bonds in the alkenes occurs, generating the alkene-derived radical cations, which sequentially enables the functionalization of translocated radical cations to occur in two ways: the first involves direct reaction with a nucleophile/radical or two molecules of nucleophiles to realize hydrofunctionalization, difunctionalization and cyclization; and the second involves the transformation of the alkene-derived radical cations into carbon-centered radicals using a base followed by radical coupling or oxidative nucleophilic coupling.
Collapse
Affiliation(s)
- Mu-Jia Luo
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
| | - Qiang Xiao
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
| | - Jin-Heng Li
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, China. .,State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China.,School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 475004, China
| |
Collapse
|
6
|
Hirata T, Ogasawara Y, Kobayashi S, Yamashita Y. Photocatalytic Addition Reactions of Ketene Silyl Acetals with Alkenes through Formation of α-Carbonyl Radicals. Chem Asian J 2022; 17:e202200647. [PMID: 35878061 DOI: 10.1002/asia.202200647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/22/2022] [Indexed: 11/08/2022]
Abstract
Addition reactions of ketene silyl acetals with alkenes that do not have an electron-withdrawing group are generally difficult because the nucleophilicity of ketene silyl acetals and the electrophilicity of alkenes are not sufficient. Herein, we report photocatalytic addition reactions of ketene silyl acetals with alkenes that proceed through formation of α-carbonyl radicals. In the presence of an appropriate protic additive, the reactions proceeded smoothly under blue-light irradiation to afford the desired products in moderate to high yields.
Collapse
Affiliation(s)
- Tsubasa Hirata
- The University of Tokyo: Tokyo Daigaku, Department of Chemistry, JAPAN
| | | | - Shu Kobayashi
- The University of Tokyo, Department of Chemistry, School of Science, 7-3-1 Hongo, Bunkyo-ku, 113-0033, Tokyo, JAPAN
| | | |
Collapse
|