1
|
Zhu SS, Lv H, Yuan X, Guo K. Photocatalytic Tricyclization of Enediynes for the Synthesis of Chromenoquinolines in Continuous Flow. Org Lett 2024; 26:8910-8915. [PMID: 39373972 DOI: 10.1021/acs.orglett.4c03359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2024]
Abstract
A photocatalyzed radical-initiated tricyclization of enediynes was developed to synthesize a range of hitherto unknown sulfonated chromenoquinolines with moderate to excellent yields under continuous operational conditions. The reaction mechanism involves a complex series of steps including alkyl radical capture by sulfur dioxide (SO2), radical addition, 6-exo-dig/6-exo-dig/6-endo-trig tricyclization, and single electron transfer (SET). This cascade of reactions results in the direct formation of a pentacyclic framework structure, along with the creation of up to three new rings and five chemical bonds in a single step. This photocatalytic protocol exhibits a diverse substrate scope, remarkable tolerance to functional groups, and scalable adaptability.
Collapse
Affiliation(s)
- Shan-Shan Zhu
- Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
| | - Hao Lv
- Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
| | - Xin Yuan
- Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
| | - Kai Guo
- Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
| |
Collapse
|
2
|
Lardy SW, Lerda VL, Schmidt VA. Polarity-Driven Thiyl Radical-Catalyzed Aerobic Debenzylation of Ethers and Amines. J Org Chem 2024; 89:15062-15067. [PMID: 39380545 DOI: 10.1021/acs.joc.4c01796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2024]
Abstract
We report the use of a strongly electrophilic thiyl radical derived from commercially available pentafluorothiophenol as a demonstration of highly chemoselective H atom abstraction from electron-rich and relatively weak benzylic C-H bonds adjacent to the O and N atoms. This approach enables the selective oxidative removal of benzyl and p-methoxybenzyl groups from amines and ethers under ambient aerobic conditions.
Collapse
Affiliation(s)
- Samuel W Lardy
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Victoria L Lerda
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Valerie A Schmidt
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| |
Collapse
|
3
|
Duari S, Biswas S, Roy A, Maity S, Elsharif AM, Biswas S. MeOTf-catalyzed Friedel-Crafts alkylation of benzoxazolones, benzothiazolones, indolinones and benzimidazolones with activated secondary alcohols. Org Biomol Chem 2024. [PMID: 39400283 DOI: 10.1039/d4ob01372g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2024]
Abstract
Herein, we have revealed a methodology for the selective C-alkylation of benzoxazolones, benzothiazolones, indolinones, and benzimidazolones incorporating activated alcohols catalysed by methyltrifluoromethanesulfonate (MeOTf). This method offers a green, atom-economic alternative for the synthesis of alkylated heterocycles, producing water as the only byproduct. Alcohols, due to their abundance, ease of preparation, and environmental friendliness, have become attractive alkylating agents. The developed reaction conditions demonstrate high yields and broad applicability across various N-alkylated heterocycles, highlighting the versatility of the MeOTf catalysis. The method was also adapted for one-pot consecutive N- and C-alkylation and chemoselective C-alkylation in heterocycles containing a free -NH group. This approach provides a practical and efficient route for the functionalization of bioactive heterocyclic compounds.
Collapse
Affiliation(s)
- Surajit Duari
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, West Bengal, India.
| | - Subrata Biswas
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, West Bengal, India.
| | - Arnab Roy
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, West Bengal, India.
| | - Srabani Maity
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, West Bengal, India.
| | - Asma M Elsharif
- Department of Chemistry, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam, 31441, Saudi Arabia
| | - Srijit Biswas
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, West Bengal, India.
| |
Collapse
|
4
|
Thakur A, Gupta SS, Sumit, Sachin, Sharma U. Visible-Light-Mediated Trifluoroalkylation of Isoquinolines via Three-Component Minisci-Type Reaction. Org Lett 2024; 26:8515-8520. [PMID: 39348629 DOI: 10.1021/acs.orglett.4c03096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/02/2024]
Abstract
A sustainable photocatalytic approach has been established for trifluoroalkylation of isoquinoline via a three-component Minisci-type reaction using a green solvent. The polarity reversal radical cascade strategy renders the selective addition of an electrophilic CF3 radical to an olefin to forge a nucleophilic C-centered radical. This multicomponent approach is operationally simple and environmentally benign with various functional groups, viz. aldehydes, acetals, amides, and halides. Mechanistic investigations were carried out to elaborate the reductive quenching catalytic pathway.
Collapse
Affiliation(s)
- Ankita Thakur
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-IHBT, Palampur 176061, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Shiv Shankar Gupta
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-IHBT, Palampur 176061, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Sumit
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-IHBT, Palampur 176061, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Sachin
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-IHBT, Palampur 176061, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Upendra Sharma
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-IHBT, Palampur 176061, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| |
Collapse
|
5
|
Schultz DC, Rathnayake U, Duncan RA, Richardson AE, Bender AM. Synthesis of the Dimeric Diarylheptanoids Alpinidinoid C and Officinine B Enabled by Blue-Light-Mediated Triple-Minisci-Type Alkylation. Org Lett 2024. [PMID: 39388634 DOI: 10.1021/acs.orglett.4c03227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
The first syntheses of the Alpinia officinarum natural products alpinidinoid C and officinine B are reported. These unusual dimeric diarylheptanoids were accessed from a 3-substituted pyridine intermediate via a blue-light-mediated, triple-Minisci-type alkylation. Very few reports utilize N-(acyloxy)phthalimides (NAPs) in the construction of natural products, and the syntheses reported herein highlight the power of this methodology toward the orthogonal construction of highly substituted arenes.
Collapse
Affiliation(s)
- Daniel C Schultz
- Warren Center for Neuroscience Drug Discovery and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Upendra Rathnayake
- Warren Center for Neuroscience Drug Discovery and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Renn A Duncan
- Warren Center for Neuroscience Drug Discovery and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Alexa E Richardson
- Warren Center for Neuroscience Drug Discovery and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Aaron M Bender
- Warren Center for Neuroscience Drug Discovery and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| |
Collapse
|
6
|
Wang W, Zhao L, Zhang Y. Generation of New Synthons for Synthesis Through Activation of Nitromethane. CHEMSUSCHEM 2024; 17:e202400454. [PMID: 38702899 DOI: 10.1002/cssc.202400454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/06/2024]
Abstract
Nitromethane is used as a common solvent, stabilizer, and fuel additive. Nitromethane has also been used as a sustainable building block and convenient reagent in chemical synthesis. In this Minireview, we summarize the recent advances in activation of nitromethane, using nitromethane as the source of cyano group, nitrogen, methylamine, formyl group, C1, nitroso, and oxime.
Collapse
Affiliation(s)
- Wenxuan Wang
- School of Ecology and Environment, Ningxia University, 489 Helan Mountain West Road, Yinchuan, 750021, China
| | - Lixing Zhao
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Yuexia Zhang
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| |
Collapse
|
7
|
Guo F, Guo Y, Sun Q, Zhang T, Wang Y, Fang L. Photoinduced HCl-Mediated Cross-Dehydrogenative Coupling of Quinolines with Alcohols and Ethers. J Org Chem 2024; 89:14204-14208. [PMID: 39265070 DOI: 10.1021/acs.joc.4c01620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2024]
Abstract
Via light irradiation, cross-dehydrogenative coupling of quinolines with alcohols and ethers was achieved under mild conditions. A stoichiometric amount of HCl and room temperature were necessary to promote the reaction. A green Minisci-type cross-dehydrogenative coupling reaction was performed without an oxidant or a transition-metal catalyst.
Collapse
Affiliation(s)
- Feixiang Guo
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Yingchang Guo
- The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Qianqian Sun
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Tao Zhang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Yakun Wang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Lizhen Fang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, China
| |
Collapse
|
8
|
An Q, Chang L, Pan H, Zuo Z. Ligand-to-Metal Charge Transfer (LMCT) Catalysis: Harnessing Simple Cerium Catalysts for Selective Functionalization of Inert C-H and C-C Bonds. Acc Chem Res 2024; 57:2915-2927. [PMID: 39291873 DOI: 10.1021/acs.accounts.4c00510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
ConspectusChemists have long pursued harnessing light energy and photoexcitation processes for synthetic transformations. Ligand-to-metal charge transfer (LMCT) in high-valent metal complexes often triggers bond homolysis, generating oxidized ligand-centered radicals and reduced metal centers. While photoinduced oxidative activations can be enabled, this process, typically seen as photochemical decomposition, remains underexplored in catalytic applications. To mitigate decomposition during LMCT excitation, we developed a catalytic cycle integrating in situ coordination, LMCT, and ligand homolysis to activate ligated alcohols transiently into alkoxy radicals. This catalytic approach leverages Ce(IV) LMCT excitation and highly reactive alkoxy radical intermediates for selective functionalizations of C(sp3)-H and C(sp3)-C(sp3) bonds under mild conditions. In this Account, we discuss these advancements, highlighting the practical utility of cost-effective cerium salts as catalysts and their potential to develop innovative transformations, addressing long-standing synthetic challenges.Selective functionalization of chemically inert C(sp3)-H bonds has long posed a significant challenge. We first detail our research using LMCT-enabled alkoxy radical-mediated hydrogen atom transfer (HAT) processes for selective C(sp3)-H functionalizations. Using readily available CeCl3, we established a general protocol for employing free alcohols in the Barton reaction. By integrating LMCT and HAT catalysis, we introduced a selective photocatalytic strategy for functionalizing feedstock alkanes, converting gaseous hydrocarbons into valuable products. Employing simple cerium salts like Ce(OTf)3 and CeCl3, we achieved selective C-H amination of methane and ethane at ambient temperature, achieving turnover numbers of 2900 and 9700, respectively. This catalytic manifold has been further exploited to address the site-selectivity challenge in the C-H functionalization of linear alkanes. The use of methanol as a cocatalyst enabled preferential functionalization of the most electron-rich sites, achieving a high intrinsic selectivity over 12:1 of secondary vs primary sites in pentane and hexane.Next, we discuss the catalytic utilization of alkoxy-radical-mediated β-scission, a frequently encountered side reaction in HAT transformations, for selective cleavage and functionalization of C-C bonds. The versatility of the LMCT catalytic platform facilitates the generation of alkoxy radicals from various free alcohols. In our initial demonstration of LMCT-enabled C(sp3)-C(sp3) bond activation, we developed a cerium-catalyzed ring-opening and amination of cycloalkanols, providing an effective protocol for cleaving unstrained C-C bonds. This strategy has been successfully applied to various radical cross-coupling processes, leading to innovative transformations such as ring expansions of cycloalkanols, dehydroxymethylative alkylation, amination, alkenylation, and ring expansions of cyclic ketones. These results highlight the synthetic potential of employing LMCT-mediated β-scission and ubiquitous C-C bonds as unconventional functional handles for generating molecular complexity.Lastly, we delve into our mechanistic investigations. Beyond the catalytic application of Ce(IV) LMCT in various transformations, we have undertaken comprehensive mechanistic studies. These investigations encompass characterization of Ce(IV) alkoxide complexes to elucidate their structures, evaluation of their photoactivity and selectivity in radical generation, and elucidation of kinetic pathways associated with transient LMCT excited states. Our research has revealed ultrafast bond homolysis, back electron transfer, and the selectivity of heteroleptic complexes in homolysis, providing crucial insights for advancing LMCT catalysis.
Collapse
Affiliation(s)
- Qing An
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Liang Chang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Hui Pan
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhiwei Zuo
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| |
Collapse
|
9
|
Liu D, Hazra A, Liu X, Maity R, Tan T, Luo L. CdS Quantum Dot Gels as a Direct Hydrogen Atom Transfer Photocatalyst for C-H Activation. Angew Chem Int Ed Engl 2024; 63:e202403186. [PMID: 38900647 DOI: 10.1002/anie.202403186] [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: 02/14/2024] [Revised: 05/13/2024] [Accepted: 06/19/2024] [Indexed: 06/22/2024]
Abstract
Here, we report CdS quantum dot (QD) gels, a three-dimensional network of interconnected CdS QDs, as a new type of direct hydrogen atom transfer (d-HAT) photocatalyst for C-H activation. We discovered that the photoexcited CdS QD gel could generate various neutral radicals, including α-amido, heterocyclic, acyl, and benzylic radicals, from their corresponding stable molecular substrates, including amides, thio/ethers, aldehydes, and benzylic compounds. Its C-H activation ability imparts a broad substrate and reaction scope. The mechanistic study reveals that this reactivity is intrinsic to CdS materials, and the neutral radical generation did not proceed via the conventional sequential electron transfer and proton transfer pathway. Instead, the C-H bonds are activated by the photoexcited CdS QD gel via a d-HAT mechanism. This d-HAT mechanism is supported by the linear correlation between the logarithm of the C-H bond activation rate constant and the C-H bond dissociation energy (BDE) with a Brønsted slope α=0.5. Our findings expand the currently limited direct hydrogen atom transfer photocatalysis toolbox and provide new possibilities for photocatalytic C-H activation.
Collapse
Affiliation(s)
- Daohua Liu
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202
| | - Atanu Hazra
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202
| | - Xiaolong Liu
- Laboratory of Theoretical and Computational Nanoscience, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100190, China
| | - Rajendra Maity
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202
| | - Ting Tan
- Laboratory of Theoretical and Computational Nanoscience, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100190, China
| | - Long Luo
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202
| |
Collapse
|
10
|
Quevedo-Flores B, Bosque I, Gonzalez-Gomez JC. Electrophotocatalytic Hydroxymethylation of Azaarenes with Methanol. Org Lett 2024; 26:7447-7451. [PMID: 39180501 PMCID: PMC11385437 DOI: 10.1021/acs.orglett.4c02797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2024]
Abstract
The merging of electrochemistry and photocatalysis allowed the required selectivity for the hydroxymethylation of functionalized azaarenes with methanol, including bioactive substrates. The two electrophotocatalytic protocols developed in this work address this transformation, using nontoxic and readily available reagents under mild reaction conditions with electricity as the only "sacrificial oxidant".
Collapse
Affiliation(s)
- Beatriz Quevedo-Flores
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Universidad de Alicante, 03080 San Vicente del Raspeig, Spain
| | - Irene Bosque
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Universidad de Alicante, 03080 San Vicente del Raspeig, Spain
| | - Jose C Gonzalez-Gomez
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Universidad de Alicante, 03080 San Vicente del Raspeig, Spain
| |
Collapse
|
11
|
Lu X, Li Y, He X, Song P, Chai Z. Heterogeneous Photocatalytic C(sp 2)-H Activation of Formate for Hydrocarboxylation of Alkenes. Chemistry 2024; 30:e202402003. [PMID: 38801064 DOI: 10.1002/chem.202402003] [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: 05/22/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 05/29/2024]
Abstract
Light-driven carboxylation offers a promising approach for synthesizing valuable fine chemicals under mild conditions. Here we disclose a heterogeneous photocatalytic strategy of C(sp2)-H activation of formate for hydrocarboxylation of alkenes over zinc indium sulfide (ZnIn2S4) under visible light. This protocol functions well with a variety of substituted styrenes with good to excellent yields; it also works for unactivated alkenes albeit with lower yields. Mechanistic studies confirm the existence of CO2⋅- as a key intermediate. It was found that C(sp2)-H activation of formate is induced by S⋅ species on the surface of ZnIn2S4 via hydrogen atom transfer (HAT) instead of a photogenerated hole oxidation mechanism. Moreover, both cleavage of the C(sp2)-H of HCOO- and formation of a benzylic anion were found to be involved in the rate-determining step for the hydrocarboxylation of styrene.
Collapse
Affiliation(s)
- Xingkai Lu
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yan Li
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Xinyuan He
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Pengfei Song
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Zhigang Chai
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| |
Collapse
|
12
|
Xu J, Liu Y, Wang Q, Tao X, Ni S, Zhang W, Yu L, Pan Y, Wang Y. Electrochemical deoxygenative amination of stabilized alkyl radicals from activated alcohols. Nat Commun 2024; 15:6116. [PMID: 39033147 PMCID: PMC11271281 DOI: 10.1038/s41467-024-50596-3] [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: 05/16/2024] [Accepted: 07/10/2024] [Indexed: 07/23/2024] Open
Abstract
Alkylamine structures represent one of the most functional and widely used in organic synthesis and drug design. However, the general methods for the functionalization of the shielded and deshielded alkyl radicals remain elusive. Here, we report a general deoxygenative amination protocol using alcohol-derived carbazates and nitrobenzene under electrochemical conditions. A range of primary, secondary, and tertiary alkylamines are obtained. This practical procedure can be scaled up through electrochemical continuous flow technique.
Collapse
Affiliation(s)
- Jia Xu
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yilin Liu
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Qing Wang
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Xiangzhang Tao
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Shengyang Ni
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Weigang Zhang
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Lei Yu
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yi Pan
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yi Wang
- Jiangsu Key Laboratory of Advanced Organic Materials, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
| |
Collapse
|
13
|
Zachmann AKZ, Drappeau JA, Liu S, Alexanian EJ. C(sp 3)-H (N-Phenyltetrazole)thiolation as an Enabling Tool for Molecular Diversification. Angew Chem Int Ed Engl 2024; 63:e202404879. [PMID: 38657161 DOI: 10.1002/anie.202404879] [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: 03/11/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Methods enabling the broad diversification of C(sp3)-H bonds from a common intermediate are especially valuable in chemical synthesis. Herein, we report a site-selective (N-phenyltetrazole)thiolation of aliphatic and (hetero)benzylic C(sp3)-H bonds using a commercially available disulfide to access N-phenyltetrazole thioethers. The thioether products are readily elaborated in diverse fragment couplings for C-C, C-O, or C-N construction. The C-H functionalization proceeds via a radical-chain pathway involving hydrogen atom transfer by the electron-poor N-phenyltetrazolethiyl radical. Hexafluoroisopropanol was found to be essential to reactions involving aliphatic C(sp3)-H thiolation, with computational analysis consistent with dual hydrogen bonding of the N-phenyltetrazolethiyl radical imparting increased radical electrophilicity to facilitate the hydrogen atom transfer. Substrate is limiting reagent in all cases, and the reaction displays an exceptional functional group tolerance well suited to applications in late-stage diversification.
Collapse
Affiliation(s)
- Ashley K Z Zachmann
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Justine A Drappeau
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Shubin Liu
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Research Computing Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Erik J Alexanian
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| |
Collapse
|
14
|
Zhang K, Li H, Wu X, Zhang D, Li Z. Positron Emission Tomography of Nitric Oxide by a Specific Radical-Generating Dihydropyridine Tracer. ACS Sens 2024; 9:2793-2800. [PMID: 38820066 DOI: 10.1021/acssensors.4c00453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
Nitric oxide (NO) plays a pivotal role as a biological signaling molecule, presenting challenges in its specific detection and differentiation from other reactive nitrogen and oxygen species within living organisms. Herein, a 18F-labeled (fluorine-18, t1/2 = 109.7 min) small-molecule tracer dimethyl 4-(4-(4-[18F]fluorobutoxy)benzyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate ([18F]BDHP) is developed based on the dihydropyridine scaffold for positron emission tomography (PET) imaging of NO in vivo. [18F]BDHP exhibits a highly sensitive and efficient C-C cleavage reaction specifically triggered by NO under physiological conditions, leading to the production of a 18F-labeled radical that is readily retained within the cells. High uptakes of [18F]BDHP are found within and around NO-generating cells, such as macrophages treated with lipopolysaccharide or benzo(a)pyrene. MicroPET/CT imaging of arthritic animal model mice reveals distinct tracer accumulation in the arthritic legs, showcasing a higher distribution of NO compared with the control legs. In summary, a specific radical-generating dihydropyridine tracer with a unique radical retention strategy has been established for the marking of NO in real-time in vivo.
Collapse
Affiliation(s)
- Kaiqiang Zhang
- State Key Laboratory of Vaccines for Infectious Diseases, Center for Molecular Imaging and Translational Medicine, Xiang An Biomedicine Laboratory, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian 361102, China
| | - Hua Li
- State Key Laboratory of Vaccines for Infectious Diseases, Center for Molecular Imaging and Translational Medicine, Xiang An Biomedicine Laboratory, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian 361102, China
| | - Xiaowei Wu
- State Key Laboratory of Vaccines for Infectious Diseases, Center for Molecular Imaging and Translational Medicine, Xiang An Biomedicine Laboratory, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian 361102, China
| | - Deliang Zhang
- State Key Laboratory of Vaccines for Infectious Diseases, Center for Molecular Imaging and Translational Medicine, Xiang An Biomedicine Laboratory, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian 361102, China
- Department of Nuclear Medicine, Xiang'an Hospital affiliated to Xiamen University, Xiamen, Fujian 361005, China
| | - Zijing Li
- State Key Laboratory of Vaccines for Infectious Diseases, Center for Molecular Imaging and Translational Medicine, Xiang An Biomedicine Laboratory, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian 361102, China
| |
Collapse
|
15
|
Deng WH, Liao RZ. Cysteine Radical and Glutamate Collaboratively Enable C-H Bond Activation and C-N Bond Cleavage in a Glycyl Radical Enzyme HplG. J Chem Inf Model 2024; 64:4168-4179. [PMID: 38745447 DOI: 10.1021/acs.jcim.4c00122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Hydroxyprolines are abundant in nature and widely utilized by many living organisms. Isomerization of trans-4-hydroxy-d-proline (t4D-HP) to generate 2-amino-4-ketopentanoate has been found to need a glycyl radical enzyme HplG, which catalyzes the cleavage of the C-N bond, while dehydration of trans-4-hydroxy-l-proline involves a homologous enzyme of HplG. Herein, molecular dynamics simulations and quantum mechanics/molecular mechanics (QM/MM) calculations are employed to understand the reaction mechanism of HplG. Two possible reaction pathways of HplG have been explored to decipher the origin of its chemoselectivity. The QM/MM calculations reveal that the isomerization proceeds via an initial hydrogen shift from the Cγ site of t4D-HP to a catalytic cysteine radical, followed by cleavage of the Cδ-N bond in t4D-HP to form a radical intermediate that captures a hydrogen atom from the cysteine. Activation of the Cδ-H bond in t4D-HP to bring about dehydration of t4D-HP possesses an extremely high energy barrier, thus rendering the dehydration pathway implausible in HplG. On the basis of the current calculations, conserved residue Glu429 plays a pivotal role in the isomerization pathway: the hydrogen bonding between it and t4D-HP weakens the hydroxyalkyl Cγ-Hγ bond, and it acts as a proton acceptor to trigger the cleavage of the C-N bond in t4D-HP. Our current QM/MM calculations rationalize the origin of the experimentally observed chemoselectivity of HplG and propose an H-bond-assisted bond activation strategy in radical-containing enzymes. These findings have general implications on radical-mediated enzymatic catalysis and expand our understanding of how nature wisely and selectively activates the C-H bond to modulate catalytic selectivity.
Collapse
Affiliation(s)
- Wen-Hao Deng
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
16
|
Kumari S, Roy S, Arora P, Kundu S. Visible light-mediated synthesis of quinazolinones and benzothiadiazine-1,1-dioxides utilizing aliphatic alcohols. Org Biomol Chem 2024; 22:4172-4178. [PMID: 38716563 DOI: 10.1039/d4ob00541d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
The activation and utilization of challenging aliphatic alcohols like methanol and ethanol is a very appealing approach to synthesize valuable organic molecules. Utilization of methanol and ethanol as a coupling partner has emerged as a valuable alternative to synthesize industrially relevant N-heterocycles because they can be easily procured from renewable sources unlike other activated coupling partners which are expensive and also unstable. Herein, a mild and metal-free photocatalytic protocol to synthesize quinazolinones and more challenging benzothiadiazine-1,1-dioxides, which is unprecedented at room temperature, is demonstrated. This methodology showcased broad substrate scope and provided important N-heterocycles more efficiently than the transition metal-based high temperature protocols. An unexplored reactivity with allyl alcohol is observed following the developed protocol. A series of control experiments were carried out to understand the mechanism.
Collapse
Affiliation(s)
- Saloni Kumari
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Souvik Roy
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Pragya Arora
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Sabuj Kundu
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| |
Collapse
|
17
|
Xue M, Pan T, Shao Z, Wang W, Li H, Zhao L, Zhou X, Zhang Y. Sustainable Electrochemical Benzylic C-H Oxidation Using MeOH as an Oxygen Source. CHEMSUSCHEM 2024; 17:e202400028. [PMID: 38225209 DOI: 10.1002/cssc.202400028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
New methods and strategies for the direct oxidation of benzylic C-H bonds are highly desirable, owing to the importance of ketone motifs in significant organic transformations and the synthesis of valuable molecules, including pharmaceuticals, pesticides, and fine chemicals. Herein, we describe an electrochemical benzylic C-H oxidation strategy for the synthesis of ketones using MeOH as an oxygen source. Inexpensive and safe KBr serves as both an electrolyte and a bromide radical precursor in the reaction. This transformation also offers several advantages such as mild conditions, broad functional group tolerance, and operational simplicity. Mechanistic investigations by control experiments, radical scavenging experiments, electron paramagnetic resonance (EPR), kinetic studies, cyclic voltammetry (CV), and in-situ Fourier transform infrared (FTIR) spectroscopy support a pathway involving the formation and transformation of benzyl methyl ether via hydrogen atom transfer (HAT) and single-electron transfer (SET). The practical application of our strategy is highlighted by the successful synthesis of five pharmaceuticals, namely lenperone, melperone, diphenhydramine, cinnarizine, and flunarizine.
Collapse
Affiliation(s)
- Meng Xue
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Tao Pan
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Zhichao Shao
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Wenxuan Wang
- School of Ecology and Environment, Ningxia University, 489 Helan Mountain West Road, Yinchuan, 750021, China
| | - Hu Li
- School of Ecology and Environment, Ningxia University, 489 Helan Mountain West Road, Yinchuan, 750021, China
| | - Lixing Zhao
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Xin Zhou
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Yuexia Zhang
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| |
Collapse
|
18
|
Lei X, Wang Y, Ma S, Jiao P. Purple Light-Promoted Coupling of Bromopyridines with Grignard Reagents via SET. J Org Chem 2024; 89:7148-7155. [PMID: 38718346 DOI: 10.1021/acs.joc.4c00525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Alkyl- and arylpyridines and 2,2'-bipyridines are conventionally prepared by Minisci reactions of pyridines and transition metal-catalyzed coupling reactions of halopyridines. Herein, purple light-promoted radical coupling reactions of 2- or 4-bromopyridines with Grignard reagents in Et2O or a mixture of Et2O and tetrahydrofuran in regular glassware without the need for a transition metal catalyst were disclosed for the first time. Methyl, primary and secondary alkyl, cycloalkyl, aryl, heteroaryl, pyridyl, and alkynyl Grignard reagents were compatible with the protocol. As a result, alkyl- and arylpyridines and 2,2'-bipyridines were easily prepared. Single electron transfer from the Grignard reagent to bromopyridine was stimulated by purple light. An electron extruded from the dimerization of the Grignard reagent worked as the catalyst. Light on/off experiments indicated that constant irradiation was required for product formation. Studies of radical clock substrates verified the involvement of a pyridyl radical from bromopyridine and the noninvolvement of an alkyl or aryl radical from the Grignard reagent. The available proof supports a photoinduced SRN mechanism for the new coupling reactions.
Collapse
Affiliation(s)
- Xingyu Lei
- College of Chemistry, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875, China
| | - Yihan Wang
- College of Chemistry, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875, China
| | - Shanshan Ma
- Institute of Rural Revitalization (Institute of Medicine and Health Care), Dezhou University, No. 566 West University Road, Dezhou 253023, China
| | - Peng Jiao
- College of Chemistry, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875, China
| |
Collapse
|
19
|
Zhan F, Lin GL, Zhang TS, Xu K, Yang YF, Li G, She Y. Pt-S Bond-Enabled Temperature-Dependent Phosphorescence in S-Heteroaryl Tetradentate Pt(S^C^N^O) Complexes. Inorg Chem 2024; 63:8822-8831. [PMID: 38696545 DOI: 10.1021/acs.inorgchem.4c00601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024]
Abstract
This study presents the rare examples of S-heteroaryl tetradentate Pt(S^C^N^O) luminescent complexes (PtSZ and PtSZtBu) containing a Pt-S bond. The presence of the Pt-S bond allows the novel Pt(S^C^N^O) complexes to exhibit temperature-dependent phosphorescent emission behavior. The PtSZtBu exhibits dual-emission phenomena and biexponential transient decay spectra above 250 K, indicating the presence of two minimal excited states in the potential energy surface (PES) of the T1 state. Through complementary experimental and computational studies, we have identified changes in orbital composition between Pt(dxy)-S(px) and Pt(dyz)-S(pz) in excited states with increasing temperature. This results in two energy minima, enabling the excited states to decay selectively and radiatively at different temperatures. Consequently, this leads to remarkable steady-state and transient emission spectra changes. Our work not only provides valuable insights for the development of novel Pt-S bond-based tetradentate Pt(II) complexes but also enhances our understanding of the distinctive properties governed by the Pt-S bond.
Collapse
Affiliation(s)
- Feng Zhan
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| | - Guo-Liang Lin
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| | - Teng-Shuo Zhang
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| | - Kewei Xu
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| | - Yun-Fang Yang
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| | - Guijie Li
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| | - Yuanbin She
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| |
Collapse
|
20
|
Bera S, Kabadwal LM, Banerjee D. Harnessing alcohols as sustainable reagents for late-stage functionalisation: synthesis of drugs and bio-inspired compounds. Chem Soc Rev 2024; 53:4607-4647. [PMID: 38525675 DOI: 10.1039/d3cs00942d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Alcohol is ubiquitous with unparalleled structural diversity and thus has wide applications as a native functional group in organic synthesis. It is highly prevalent among biomolecules and offers promising opportunities for the development of chemical libraries. Over the last decade, alcohol has been extensively used as an environmentally friendly chemical for numerous organic transformations. In this review, we collectively discuss the utilisation of alcohol from 2015 to 2023 in various organic transformations and their application toward intermediates of drugs, drug derivatives and natural product-like molecules. Notable features discussed are as follows: (i) sustainable approaches for C-X alkylation (X = C, N, or O) including O-phosphorylation of alcohols, (ii) newer strategies using methanol as a methylating reagent, (iii) allylation of alkenes and alkynes including allylic trifluoromethylations, (iv) alkenylation of N-heterocycles, ketones, sulfones, and ylides towards the synthesis of drug-like molecules, (v) cyclisation and annulation to pharmaceutically active molecules, and (vi) coupling of alcohols with aryl halides or triflates, aryl cyanide and olefins to access drug-like molecules. We summarise the synthesis of over 100 drugs via several approaches, where alcohol was used as one of the potential coupling partners. Additionally, a library of molecules consisting over 60 fatty acids or steroid motifs is documented for late-stage functionalisation including the challenges and opportunities for harnessing alcohols as renewable resources.
Collapse
Affiliation(s)
- Sourajit Bera
- Department of Chemistry, Laboratory of Catalysis and Organic Synthesis, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India.
| | - Lalit Mohan Kabadwal
- Department of Chemistry, Laboratory of Catalysis and Organic Synthesis, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India.
| | - Debasis Banerjee
- Department of Chemistry, Laboratory of Catalysis and Organic Synthesis, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India.
| |
Collapse
|
21
|
Mantry L, Gandeepan P. Visible-Light-Induced PhI(OAc) 2-Mediated Alkylation of Heteroarenes with Simple Alkanes and Ethers. J Org Chem 2024; 89:6539-6544. [PMID: 38642055 DOI: 10.1021/acs.joc.4c00140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2024]
Abstract
The direct alkylation of heteroarenes with alkanes has been successfully achieved through visible-light-induced hypervalent iodine-mediated C-H functionalization of both coupling partners at ambient temperatures. This reaction proceeds via the in situ generation of nucleophilic alkyl radicals from alkanes through hydrogen atom transfer (HAT), followed by a Minisci-type reaction with heteroarenes. These mild reaction conditions have demonstrated their suitability for the alkylation of a wide range of heterocycles, including azoles, pyridines, quinolines, isoquinolines, and quinoxalinones.
Collapse
Affiliation(s)
- Lusina Mantry
- Department of Chemistry, Indian Institute of Technology Tirupati, Yerpedu - Venkatagiri Road, Yerpedu Post, Tirupati District, Andhra Pradesh, India - 517619
| | - Parthasarathy Gandeepan
- Department of Chemistry, Indian Institute of Technology Tirupati, Yerpedu - Venkatagiri Road, Yerpedu Post, Tirupati District, Andhra Pradesh, India - 517619
| |
Collapse
|
22
|
Choi W, Kim L, Hong S. Unraveling the Potential of Vinyl Ether as an Ethylene Surrogate in Heteroarene C─H Functionalization via the Spin-Center Shift. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309800. [PMID: 38477022 PMCID: PMC11109664 DOI: 10.1002/advs.202309800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Despite the simplicity and abundance of ethylene, its practical application presents significant hurdles due to its nature as a highly flammable gas. Herein, a strategic use of easily handled vinyl ether is reported as a latent ethylene surrogate achieved via a spin-center shift (SCS) pathway, enabling the successful three-component reaction that bridges heteroarenes and various coupling partners, including sulfinates, thiols, and phosphine oxides. Through a photoredox catalytic process, α-oxy radicals are generated by combining various radicals with phenyl vinyl ether, which are subsequently added to N-heteroarenes. Subsequently, the radical-mediated SCS pathway serves as the driving force for C─O bond cleavage, effectively engaging the phenoxy group as a leaving group. In addition, by broadening the utility of the method, a valuable synthon is provided for efficient C─H vinylation of N-heteroarenes following sulfonyl group elimination. This approach not only enriches the toolbox of synthetic methodology but also provides a more streamlined alternative, circumventing the challenges associated with direct ethylene gas usage. The versatility of the method, particularly evident in late-stage functionalizations of medicinally relevant molecules and peptides, underscores its capability to produce invaluable three-component compounds and vinylated N-heteroarene derivatives.
Collapse
Affiliation(s)
- Wonjun Choi
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Catalytic Hydrocarbon FunctionalizationsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
| | - Leejae Kim
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Catalytic Hydrocarbon FunctionalizationsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
| | - Sungwoo Hong
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Catalytic Hydrocarbon FunctionalizationsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
| |
Collapse
|
23
|
Long A, Oswood CJ, Kelly CB, Bryan MC, MacMillan DWC. Couple-close construction of polycyclic rings from diradicals. Nature 2024; 628:326-332. [PMID: 38480891 PMCID: PMC11487475 DOI: 10.1038/s41586-024-07181-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/08/2024] [Indexed: 04/06/2024]
Abstract
Heteroarenes are ubiquitous motifs in bioactive molecules, conferring favourable physical properties when compared to their arene counterparts1-3. In particular, semisaturated heteroarenes possess attractive solubility properties and a higher fraction of sp3 carbons, which can improve binding affinity and specificity. However, these desirable structures remain rare owing to limitations in current synthetic methods4-6. Indeed, semisaturated heterocycles are laboriously prepared by means of non-modular fit-for-purpose syntheses, which decrease throughput, limit chemical diversity and preclude their inclusion in many hit-to-lead campaigns7-10. Herein, we describe a more intuitive and modular couple-close approach to build semisaturated ring systems from dual radical precursors. This platform merges metallaphotoredox C(sp2)-C(sp3) cross-coupling with intramolecular Minisci-type radical cyclization to fuse abundant heteroaryl halides with simple bifunctional feedstocks, which serve as the diradical synthons, to rapidly assemble a variety of spirocyclic, bridged and substituted saturated ring types that would be extremely difficult to make by conventional methods. The broad availability of the requisite feedstock materials allows sampling of regions of underexplored chemical space. Reagent-controlled radical generation leads to a highly regioselective and stereospecific annulation that can be used for the late-stage functionalization of pharmaceutical scaffolds, replacing lengthy de novo syntheses.
Collapse
Affiliation(s)
- Alice Long
- Merck Center for Catalysis at Princeton University, Princeton, NJ, USA
| | | | - Christopher B Kelly
- Discovery Process Research, Janssen Research and Development LLC, Spring House, PA, USA
| | - Marian C Bryan
- Therapeutics Discovery, Janssen Research and Development LLC, Spring House, PA, USA
| | | |
Collapse
|
24
|
Chai Z. Heterogeneous Photocatalytic Strategies for C(sp 3 )-H Activation. Angew Chem Int Ed Engl 2024; 63:e202316444. [PMID: 38225893 DOI: 10.1002/anie.202316444] [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: 10/31/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
Activation of ubiquitous C(sp3 )-H bonds is extremely attractive but remains a great challenge. Heterogeneous photocatalysis offers a promising and sustainable approach for C(sp3 )-H activation and has been fast developing in the past decade. This Minireview focuses on mechanism and strategies for heterogeneous photocatalytic C(sp3 )-H activation. After introducing mechanistic insights, heterogeneous photocatalytic strategies for C(sp3 )-H activation including precise design of active sites, regulation of reactive radical species, improving charge separation and reactor innovations are discussed. In addition, recent advances in C(sp3 )-H activation of hydrocarbons, alcohols, ethers, amines and amides by heterogeneous photocatalysis are summarized. Lastly, challenges and opportunities are outlined to encourage more efforts for the development of this exciting and promising field.
Collapse
Affiliation(s)
- Zhigang Chai
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| |
Collapse
|
25
|
Xiong Y, Zhang Q, Zhang J, Wu X. Visible-Light-Driven Deoxygenative Heteroarylation of Alcohols with Heteroaryl Sulfones. J Org Chem 2024; 89:3629-3634. [PMID: 38364202 DOI: 10.1021/acs.joc.3c02733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
The visible-light-promoted deoxygenative radical heteroarylation of alcohols was achieved in the absence of any external photosensitizers. The processes occur through the generation of xanthate salts from alcohols, followed by SET and fragmentation, delivering alkyl radicals to react with heteroaryl sulfones. This method is amenable for a wide range of alcohols with good functional group tolerance, providing a practical strategy for the alkylation of benzo-heteroaromatics. Mechanism studies indicate that direct visible-light excitation of xanthate anions and subsequent SET initiate the reactions.
Collapse
Affiliation(s)
- Yanjiao Xiong
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| | - Qi Zhang
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| | - Jun Zhang
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| | - Xuesong Wu
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| |
Collapse
|
26
|
Yang Y, Zhu H, Gong B, Yang H, Fan Q, Le ZG, Xie Z. Neutral nickel-catalyzed dehydrosulfonylation of unactivated allylic alcohols under mild conditions. Chem Commun (Camb) 2024; 60:2516-2519. [PMID: 38324066 DOI: 10.1039/d3cc06036e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Allyl sulfones are important sulfur-containing compounds that have widespread applications in organic synthesis, medicinal chemistry and materials science. Herein, nickel-catalysed dehydrosulfonylation of unactivated allyl alcohols with aryl sulfonyl hydrazides without additional active agents under mild conditions was developed. A variety of functional allyl sulfones could be efficiently synthesized in the presence of air-stable Ni(acac)2 as the catalyst and 1,1'-bis(diphenylphosphino)ferrocene (DPPF) as the ligand.
Collapse
Affiliation(s)
- Yahui Yang
- School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China.
| | - Haibo Zhu
- School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China.
| | - Bozhen Gong
- School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China.
| | - Hong Yang
- School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China.
| | - Qiangwen Fan
- School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China.
| | - Zhang-Gao Le
- School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China.
| | - Zongbo Xie
- School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China.
| |
Collapse
|
27
|
Wang C, Liu X, Wang Q, Fang WH, Chen X. Unveiling Mechanistic Insights and Photocatalytic Advancements in Intramolecular Photo-(3 + 2)-Cycloaddition: A Comparative Assessment of Two Paradigmatic Single-Electron-Transfer Models. JACS AU 2024; 4:419-431. [PMID: 38425917 PMCID: PMC10900211 DOI: 10.1021/jacsau.3c00542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/29/2023] [Accepted: 11/29/2023] [Indexed: 03/02/2024]
Abstract
The synthesis of 1-aminonorbornane (1-aminoNB), a potential aniline bioisostere, through photochemistry or photoredox catalysis signifies a remarkable breakthrough with implications in organic chemistry, pharmaceutical chemistry, and sustainable chemistry. However, an understanding of the underlying mechanisms involved in these reactions remains limited and ambiguous. Herein, we employ high-precision CASPT2//CASSCF calculations to elucidate the intricate mechanisms regulating the intramolecular photo-(3 + 2)-cycloaddition reactions for the synthesis of 1-aminoNB in the presence or absence of the Ir-complex-based photocatalyst. Our investigations delve into radical cascades, stereoselectivity, particularly single-electron-transfer (SET) events, etc. Furthermore, we innovatively introduce and compare two SET models integrating Marcus electron-transfer theory and transition-state theory. These models combined with kinetic data contribute to recognizing the critical control factors in diverse photocatalysis, thereby guiding the design and manipulation of photoredox catalysis as well as the improvement and modification of photocatalysts.
Collapse
Affiliation(s)
- Chu Wang
- College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Xiao Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Qian Wang
- College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Wei-Hai Fang
- College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Xuebo Chen
- College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| |
Collapse
|
28
|
Fan X, Zhang D, Xiu X, Xu B, Yuan Y, Chen F, Gao P. Nucleophilic functionalization of thianthrenium salts under basic conditions. Beilstein J Org Chem 2024; 20:257-263. [PMID: 38352071 PMCID: PMC10862136 DOI: 10.3762/bjoc.20.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/02/2024] [Indexed: 02/16/2024] Open
Abstract
In recent years, S-(alkyl)thianthrenium salts have become an important means of functionalizing alcohol compounds. However, additional transition metal catalysts and/or visible light are required. Herein, a direct thioetherification/amination reaction of thianthrenium salts is realized under metal-free conditions. This strategy exhibits good functional-group tolerance, operational simplicity, and an extensive range of compatible substrates.
Collapse
Affiliation(s)
- Xinting Fan
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Duo Zhang
- Medicine Center, Guangxi University of Science and Technology, Liushi Road 257, Liuzhou, Guangxi 545006, China
| | - Xiangchuan Xiu
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Bin Xu
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Yu Yuan
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Feng Chen
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Pan Gao
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| |
Collapse
|
29
|
Cao X, Wei L, Yang J, Song H, Wei Y. A visible-light-induced bromine radical initiates direct C-H alkylation of heteroaromatics. Org Biomol Chem 2024; 22:1157-1161. [PMID: 38224149 DOI: 10.1039/d3ob02047a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Herein, a photoinduced direct C(sp2)-H alkylation of N-heteroaromatics by using commercially available tetrabutylammonium tribromide (TBATB) as a HAT reagent is described. The method uses O2 as the oxidant, and features metal-free, mild reaction conditions and good functional group compatibility.
Collapse
Affiliation(s)
- Xiangxue Cao
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi, 832003, China.
| | - Lanfeng Wei
- Xinjiang Key Laboratory of Coal Mine Disaster Intelligent Prevention and Emergency Response, Xinjiang Institute of Engineering, Urumqi 830023, China.
| | - Jinbo Yang
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi, 832003, China.
| | - Huanhuan Song
- Bingtuan Energy Development Institute, Shihezi University, Shihezi, 832003, China.
| | - Yu Wei
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi, 832003, China.
| |
Collapse
|
30
|
Xu GQ, Wang WD, Xu PF. Photocatalyzed Enantioselective Functionalization of C(sp 3)-H Bonds. J Am Chem Soc 2024; 146:1209-1223. [PMID: 38170467 DOI: 10.1021/jacs.3c06169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Owing to its diverse activation processes including single-electron transfer (SET) and hydrogen-atom transfer (HAT), visible-light photocatalysis has emerged as a sustainable and efficient platform for organic synthesis. These processes provide a powerful avenue for the direct functionalization of C(sp3)-H bonds under mild conditions. Over the past decade, there have been remarkable advances in the enantioselective functionalization of the C(sp3)-H bond via photocatalysis combined with conventional asymmetric catalysis. Herein, we summarize the advances in asymmetric C(sp3)-H functionalization involving visible-light photocatalysis and discuss two main pathways in this emerging field: (a) SET-driven carbocation intermediates are followed by stereospecific nucleophile attacks; and (b) photodriven alkyl radical intermediates are further enantioselectively captured by (i) chiral π-SOMOphile reagents, (ii) stereoselective transition-metal complexes, and (iii) another distinct stereoscopic radical species. We aim to summarize key advances in reaction design, catalyst development, and mechanistic understanding, to provide new insights into this rapidly evolving area of research.
Collapse
Affiliation(s)
- Guo-Qiang Xu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, MOE Frontiers Science Center for Rare Isotopes, Lanzhou Magnetic Resonance Center, Lanzhou University, Lanzhou 730000, P.R. China
| | - Wei David Wang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, MOE Frontiers Science Center for Rare Isotopes, Lanzhou Magnetic Resonance Center, Lanzhou University, Lanzhou 730000, P.R. China
| | - Peng-Fei Xu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, MOE Frontiers Science Center for Rare Isotopes, Lanzhou Magnetic Resonance Center, Lanzhou University, Lanzhou 730000, P.R. China
| |
Collapse
|
31
|
Li QY, He Y, Lin YM, Gong L. Photo-Induced C-H Methylation Reactions. Chemistry 2023; 29:e202302542. [PMID: 37800464 DOI: 10.1002/chem.202302542] [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: 08/04/2023] [Revised: 09/21/2023] [Accepted: 10/04/2023] [Indexed: 10/07/2023]
Abstract
Direct C-H methylation is a highly valuable approach for introducing methyl groups into organic molecules, particularly in pharmaceutical chemistry. Among the various methodologies available, photo-induced methylation stands out as an exceptional choice due to its mild reaction conditions, energy efficiency, and compatibility with functional groups. This article offers a comprehensive review of photochemical strategies employed for the direct and selective methylation of C(sp3 )-H, C(sp2 )-H, and C(sp)-H bonds in various organic molecules. The discussed methodologies encompass transition-metal-based photocatalysis, organophotocatalysis, as well as other metal-free approaches, including electron donor-acceptor (EDA)-enabled transformations. Importantly, a wide range of easily accessible agents such as tert-butyl peroxide, methanol, DMSO, methyl tert-butyl ether, TsOMe, N-(acetoxy)phthalimide, acetic acid, methyl halides, and even methane can serve as effective methylating reagents for modifying diverse targets. These advancements in photochemical C-H methylation are anticipated to drive further progress in the fields of organic synthesis, photocatalysis, and pharmaceutical development, opening up exciting avenues for creating novel organic molecules and discovering new drug compounds.
Collapse
Affiliation(s)
- Qian-Yu Li
- Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Yuhang He
- Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Yu-Mei Lin
- Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Lei Gong
- Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, China
- Innovation Laboratory for Sciences and, Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, Fujian, 361005, China
| |
Collapse
|
32
|
Rubanov ZM, Levin VV, Dilman AD. One-Pot Transformation of Aldehydes to Ketones via Minisci-Type Reaction of Imines. Org Lett 2023. [PMID: 38016095 DOI: 10.1021/acs.orglett.3c03764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
A method for the conversion of aldehydes to ketones via the preliminary formation of aldiminines is described. The imines are involved in acid promoted Minisci-type reaction with alkyl radicals generated from esters of N-hydroxylphthalimide under photoredox conditions. Aminyl radical cations formed after the addition of the iminium ions are believed to be key intermediates, which determine the reaction outcome.
Collapse
Affiliation(s)
- Zakhar M Rubanov
- N. D. Zelinsky Institute of Organic Chemistry, 119991 Moscow, Leninsky prosp. 47, Russian Federation
- Mendeleev University of Chemical Technology, Miusskaya Sq., 9, Moscow 125047, Russian Federation
| | - Vitalij V Levin
- N. D. Zelinsky Institute of Organic Chemistry, 119991 Moscow, Leninsky prosp. 47, Russian Federation
| | - Alexander D Dilman
- N. D. Zelinsky Institute of Organic Chemistry, 119991 Moscow, Leninsky prosp. 47, Russian Federation
| |
Collapse
|
33
|
Liu X, Lu M, Guo X, Xu H, Xu J. Visible-Light Enabled Dehydroxylative Alkylation of α-Hydroxy Carboxylic Acid Derivatives via C-O Bond Cleavage. Chemistry 2023; 29:e202302041. [PMID: 37507840 DOI: 10.1002/chem.202302041] [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: 06/27/2023] [Revised: 07/28/2023] [Accepted: 07/28/2023] [Indexed: 07/30/2023]
Abstract
A novel visible-light photoredox strategy is reported for the efficient dehydroxylative alkylation of a wide array of α-hydroxy carboxylic acid derivatives using diaryl boron radical. The reaction features readily accessible starting materials, broad substrate scope with excellent functionality tolerance. Preliminary mechanistic studies reveal that the spin-center shift process is responsible for the C-O bond activation, which is promoted by the diaryl boron radical generated from bench-stable and commercially available tetraphenyl borate (NaBPh4 ).
Collapse
Affiliation(s)
- Xiaobo Liu
- School of Food and Biological Engineering, Anhui Province Key Laboratory of, Advance Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei, 230009, P. R. China
| | - Minming Lu
- School of Food and Biological Engineering, Anhui Province Key Laboratory of, Advance Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei, 230009, P. R. China
| | - Xiangli Guo
- School of Food and Biological Engineering, Anhui Province Key Laboratory of, Advance Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei, 230009, P. R. China
| | - Huajian Xu
- School of Food and Biological Engineering, Anhui Province Key Laboratory of, Advance Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei, 230009, P. R. China
| | - Jun Xu
- School of Food and Biological Engineering, Anhui Province Key Laboratory of, Advance Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei, 230009, P. R. China
| |
Collapse
|
34
|
Wang Y, Dana S, Long H, Xu Y, Li Y, Kaplaneris N, Ackermann L. Electrochemical Late-Stage Functionalization. Chem Rev 2023; 123:11269-11335. [PMID: 37751573 PMCID: PMC10571048 DOI: 10.1021/acs.chemrev.3c00158] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Indexed: 09/28/2023]
Abstract
Late-stage functionalization (LSF) constitutes a powerful strategy for the assembly or diversification of novel molecular entities with improved physicochemical or biological activities. LSF can thus greatly accelerate the development of medicinally relevant compounds, crop protecting agents, and functional materials. Electrochemical molecular synthesis has emerged as an environmentally friendly platform for the transformation of organic compounds. Over the past decade, electrochemical late-stage functionalization (eLSF) has gained major momentum, which is summarized herein up to February 2023.
Collapse
Affiliation(s)
| | | | | | - Yang Xu
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Yanjun Li
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Nikolaos Kaplaneris
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Lutz Ackermann
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| |
Collapse
|
35
|
Motz R, Sun AC, Lehnherr D, Ruccolo S. High-Throughput Determination of Stern-Volmer Quenching Constants for Common Photocatalysts and Quenchers. ACS ORGANIC & INORGANIC AU 2023; 3:266-273. [PMID: 37810410 PMCID: PMC10557125 DOI: 10.1021/acsorginorgau.3c00019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 10/10/2023]
Abstract
Mechanistic information on reactions proceeding via photoredox catalysis has enabled rational optimizations of existing reactions and revealed new synthetic pathways. One essential step in any photoredox reaction is catalyst quenching via photoinduced electron transfer or energy transfer with either a substrate, additive, or cocatalyst. Identification of the correct quencher using Stern-Volmer studies is a necessary step for mechanistic understanding; however, such studies are often cumbersome, low throughput and require specialized luminescence instruments. This report describes a high-throughput method to rapidly acquire a series of Stern-Volmer constants, employing readily available fluorescence plate readers and 96-well plates. By leveraging multichannel pipettors or liquid dispensing robots in combination with fast plate readers, the sampling frequency for quenching studies can be improved by several orders of magnitude. This new high-throughput method enabled the rapid collection of 220 quenching constants for a library of 20 common photocatalysts with 11 common quenchers. The extensive Stern-Volmer constant table generated greatly facilitates the systematic comparison between quenchers and can provide guidance to the synthetic community interested in designing and understanding catalytic photoredox reactions.
Collapse
Affiliation(s)
- Rachel
N. Motz
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Alexandra C. Sun
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Dan Lehnherr
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Serge Ruccolo
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| |
Collapse
|
36
|
Li H, Li C, Liu W, Yao Y, Li Y, Zhang B, Qiu C. Photo-Induced C 1 Substitution Using Methanol as a C 1 Source. CHEMSUSCHEM 2023; 16:e202300377. [PMID: 37140478 DOI: 10.1002/cssc.202300377] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/04/2023] [Accepted: 05/04/2023] [Indexed: 05/05/2023]
Abstract
The development of sustainable and efficient C1 substitution methods is of central interest for organic synthesis and pharmaceuticals production, the methylation motifs bound to a carbon, nitrogen, or oxygen atom widely exist in natural products and top-selling drugs. In the past decades, a number of methods involving green and inexpensive methanol have already been disclosed to replace industrial hazardous and waste-generating C1 source. Among the various efforts, photochemical strategy is considered as a "renewable" alternative that shows great potential to selectively activate methanol to achieve a series of C1 substitutions at mild conditions, typically C/N-methylation, methoxylation, hydroxymethylation, and formylation. Herein the recent advances in selective transformation of methanol to various C1 functional groups via well-designed photochemical systems involving different types of catalysts or not is systematically reviewed. Both the mechanism and corresponding photocatalytic system were discussed and classified on specific methanol activation models. Finally, the major challenges and perspectives are proposed.
Collapse
Affiliation(s)
- Hongmei Li
- College of Mechanical Engineering, College of Food and Bioengineering, Chengdu University, Chengdu, 610106, P.R. China
| | - Chao Li
- College of Mechanical Engineering, College of Food and Bioengineering, Chengdu University, Chengdu, 610106, P.R. China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, P.R. China
| | - Wei Liu
- International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, P.R. China
| | - Yanling Yao
- School of Chemistry and Materials Engineering, Huizhou University, Huizhou, 516007, P.R. China
| | - Yuanhua Li
- School of Chemistry and Materials Engineering, Huizhou University, Huizhou, 516007, P.R. China
| | - Bing Zhang
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, P.R. China
- State Key Laboratory of Chemical Engineering, Institute of Pharmaceutical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Chuntian Qiu
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, P.R. China
- International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, P.R. China
| |
Collapse
|
37
|
He Z, Moreno JA, Swain M, Wu J, Kwon O. Aminodealkenylation: Ozonolysis and copper catalysis convert C(sp 3)-C(sp 2) bonds to C(sp 3)-N bonds. Science 2023; 381:877-886. [PMID: 37616345 PMCID: PMC10753956 DOI: 10.1126/science.adi4758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/25/2023] [Indexed: 08/26/2023]
Abstract
Great efforts have been directed toward alkene π bond amination. In contrast, analogous functionalization of the adjacent C(sp3)-C(sp2) σ bonds is much rarer. Here we report how ozonolysis and copper catalysis under mild reaction conditions enable alkene C(sp3)-C(sp2) σ bond-rupturing cross-coupling reactions for the construction of new C(sp3)-N bonds. We have used this unconventional transformation for late-stage modification of hormones, pharmaceutical reagents, peptides, and nucleosides. Furthermore, we have coupled abundantly available terpenes and terpenoids with nitrogen nucleophiles to access artificial terpenoid alkaloids and complex chiral amines. In addition, we applied a commodity chemical, α-methylstyrene, as a methylation reagent to prepare methylated nucleosides directly from canonical nucleosides in one synthetic step. Our mechanistic investigation implicates an unusual copper ion pair cooperative process.
Collapse
Affiliation(s)
- Zhiqi He
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Jose Antonio Moreno
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Manisha Swain
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Jason Wu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Ohyun Kwon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| |
Collapse
|
38
|
Ma X, Wang L, Meng X, Li W, Wang Q, Gu Y, Qiu L. NHC-mediated photocatalytic deoxygenation of alcohols for the synthesis of internal alkynes via a Csp 3-Csp coupling reaction. Org Biomol Chem 2023; 21:6693-6696. [PMID: 37548245 DOI: 10.1039/d3ob01066j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
NHC-mediated deoxygenation of alcohols under photocatalytic conditions is described. The process provides various alkyl radicals, which can react with 1-bromoalkyne via Csp3-Csp coupling to afford internal alkynes in moderate to good yields. The method offers a new and convenient approach to synthesize internal alkynes.
Collapse
Affiliation(s)
- Xueji Ma
- School of Pharmacy, Key Laboratory of Nano-carbon Modified Film Technology Engineering of Henan Province, Xinxiang University, Xinxiang 453000, P. R. China.
| | - Liujie Wang
- School of Pharmacy, Key Laboratory of Nano-carbon Modified Film Technology Engineering of Henan Province, Xinxiang University, Xinxiang 453000, P. R. China.
| | - Xiaoqing Meng
- School of Pharmacy, Key Laboratory of Nano-carbon Modified Film Technology Engineering of Henan Province, Xinxiang University, Xinxiang 453000, P. R. China.
| | - Wenbo Li
- School of Pharmacy, Key Laboratory of Nano-carbon Modified Film Technology Engineering of Henan Province, Xinxiang University, Xinxiang 453000, P. R. China.
| | - Qin Wang
- School of Pharmacy, Key Laboratory of Nano-carbon Modified Film Technology Engineering of Henan Province, Xinxiang University, Xinxiang 453000, P. R. China.
| | - Yuke Gu
- School of Pharmacy, Key Laboratory of Nano-carbon Modified Film Technology Engineering of Henan Province, Xinxiang University, Xinxiang 453000, P. R. China.
| | - Lingna Qiu
- School of Pharmacy, Key Laboratory of Nano-carbon Modified Film Technology Engineering of Henan Province, Xinxiang University, Xinxiang 453000, P. R. China.
| |
Collapse
|
39
|
Meger FS, Murphy JA. Recent Advances in C-H Functionalisation through Indirect Hydrogen Atom Transfer. Molecules 2023; 28:6127. [PMID: 37630379 PMCID: PMC10459052 DOI: 10.3390/molecules28166127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
The functionalisation of C-H bonds has been an enormous achievement in synthetic methodology, enabling new retrosynthetic disconnections and affording simple synthetic equivalents for synthons. Hydrogen atom transfer (HAT) is a key method for forming alkyl radicals from C-H substrates. Classic reactions, including the Barton nitrite ester reaction and Hofmann-Löffler-Freytag reaction, among others, provided early examples of HAT. However, recent developments in photoredox catalysis and electrochemistry have made HAT a powerful synthetic tool capable of introducing a wide range of functional groups into C-H bonds. Moreover, greater mechanistic insights into HAT have stimulated the development of increasingly site-selective protocols. Site-selectivity can be achieved through the tuning of electron density at certain C-H bonds using additives, a judicious choice of HAT reagent, and a solvent system. Herein, we describe the latest methods for functionalizing C-H/Si-H/Ge-H bonds using indirect HAT between 2018-2023, as well as a critical discussion of new HAT reagents, mechanistic aspects, substrate scopes, and background contexts of the protocols.
Collapse
Affiliation(s)
- Filip S. Meger
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, 16 Avinguda dels Països Catalans, 43007 Tarragona, Catalonia, Spain
| | - John A. Murphy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UK
| |
Collapse
|
40
|
Győrfi N, Tasnádi G, Gyuris M, Kotschy A. Visible-Light-Induced Synthesis of Branched Ethers via Multicomponent Reactions. J Org Chem 2023. [PMID: 37418511 DOI: 10.1021/acs.joc.3c00804] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
The Spin-Center Shift (SCS) elimination is a specific way for the generation of radicals with relevance in synthetic and biochemical pathways. The combination of SCS-mediated radical chemistry and atom-transfer radical addition (ATRA) offers new directions in diversity-oriented chemical synthesis. Herein, we report a photoredox three-component reaction of α-acyloxy-N-heterocycles as radical precursors, styrene derivatives as radical trapping agents, and alcohols as nucleophilic quenchers. The novel radical-polar crossover reaction provides access to a diverse set of branched ethers possessing high structural complexity. The utility of the transformation was also demonstrated by the synthesis of a complex drug derivative and it was easily scalable to the multigram level. The scope and limitations were also explored and a plausible mechanism was proposed.
Collapse
Affiliation(s)
- Nándor Győrfi
- Servier Research Institute of Medicinal Chemistry, Záhony u 7, 1031 Budapest, Hungary
- Eötvös Loránd University, Institute of Chemistry, Pázmány Péter s. 1/A, 1117 Budapest, Hungary
| | - Gábor Tasnádi
- Servier Research Institute of Medicinal Chemistry, Záhony u 7, 1031 Budapest, Hungary
| | - Márió Gyuris
- Servier Research Institute of Medicinal Chemistry, Záhony u 7, 1031 Budapest, Hungary
| | - Andras Kotschy
- Servier Research Institute of Medicinal Chemistry, Záhony u 7, 1031 Budapest, Hungary
| |
Collapse
|
41
|
Yan C, Zhang M, Li J, Zhang J, Wu Y. Thiol-promoted intermolecular cyclization to synthesize 1,2,4-oxadiazoles including tioxazafen under transition metal-free conditions. Org Biomol Chem 2023. [PMID: 37376991 DOI: 10.1039/d3ob00770g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
A simple and efficient one-pot intermolecular annulation reaction for the synthesis of 1,2,4-oxadiazoles from amidoximes and benzyl thiols has been developed, in which benzyl thiols act as not only reactants but also organo-catalysts. The control experiments proved that thiol substrates could facilitate the dehydroaromatization step. High yield, functional group diversity and transition metal-free, extra oxidant-free, and mild conditions are the important practical features. Moreover, this protocol provides an effective alternative method for the synthesis of a commercially available broad-spectrum nematicide, tioxazafen.
Collapse
Affiliation(s)
- Congcong Yan
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Min Zhang
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Jiaxin Li
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Jinli Zhang
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China
- Henan Key Laboratory of Chemical Biology and Organic Chemistry; Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou, 450052, P.R. China.
| | - Yangjie Wu
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China
- Henan Key Laboratory of Chemical Biology and Organic Chemistry; Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou, 450052, P.R. China.
| |
Collapse
|
42
|
Abstract
Azines, such as pyridines, quinolines, pyrimidines, and pyridazines, are widespread components of pharmaceuticals. Their occurrence derives from a suite of physiochemical properties that match key criteria in drug design and is tunable by varying their substituents. Developments in synthetic chemistry, therefore, directly impact these efforts, and methods that can install various groups from azine C-H bonds are particularly valuable. Furthermore, there is a growing interest in late-stage functionalization (LSF) reactions that focus on advanced candidate compounds that are often complex structures with multiple heterocycles, functional groups, and reactive sites. Because of factors such as their electron-deficient nature and the effects of the Lewis basic N atom, azine C-H functionalization reactions are often distinct from their arene counterparts, and the application of these reactions in LSF contexts is difficult. However, there have been many significant advances in azine LSF reactions, and this review will describe this progress, much of which has occurred over the past decade. It is possible to categorize these reactions as radical addition processes, metal-catalyzed C-H activation reactions, and transformations occurring via dearomatized intermediates. Substantial variation in reaction design within each category indicates both the rich reactivity of these heterocycles and the creativity of the approaches involved.
Collapse
Affiliation(s)
- Celena M Josephitis
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Hillary M H Nguyen
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Andrew McNally
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| |
Collapse
|
43
|
Yang H, Xu J, Cao H, Wu J, Zhao D. Recovery of homogeneous photocatalysts by covalent organic framework membranes. Nat Commun 2023; 14:2726. [PMID: 37169759 PMCID: PMC10175538 DOI: 10.1038/s41467-023-38424-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 05/03/2023] [Indexed: 05/13/2023] Open
Abstract
Transition metal-based homogeneous photocatalysts offer a wealth of opportunities for organic synthesis. The most versatile ruthenium(II) and iridium(III) polypyridyl complexes, however, are among the rarest metal complexes. Moreover, immobilizing these precious catalysts for recycling is challenging as their opacity may obstruct light transmission. Recovery of homogeneous catalysts by conventional polymeric membranes is promising but limited, as the modulation of their pore structure and tolerance of polar organic solvents are challenging. Here, we report the effective recovery of homogeneous photocatalysts using covalent organic framework (COF) membranes. An array of COF membranes with tunable pore sizes and superior organic solvent resistance were prepared. Ruthenium and iridium photoredox catalysts were recycled for 10 cycles in various types of photochemical reactions, constantly achieving high catalytical performance, high recovery rates, and high permeance. We successfully recovered the photocatalysts at gram-scale. Furthermore, we demonstrated a cascade isolation of an iridium photocatalyst and purification of a small organic molecule product with COF membranes possessing different pore sizes. Our results indicate an intriguing potential to shift the paradigm of the pharmaceutical and fine chemical synthesis campaign.
Collapse
Affiliation(s)
- Hao Yang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore
| | - Jinhui Xu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Hui Cao
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Jie Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
| | - Dan Zhao
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore.
| |
Collapse
|
44
|
Ni P, Yang L, Yang J, Cheng R, Zhu W, Ma Y, Ye J. para-Selective, Direct C(sp 2)-H Alkylation of Electron-Deficient Arenes by the Electroreduction Process. J Org Chem 2023; 88:5248-5253. [PMID: 37023248 DOI: 10.1021/acs.joc.2c02412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Direct para-selective C(sp2)-H alkylation of electron-deficient arenes based on the electroreduction-enabled radical addition of alkyl bromides has been developed under mild conditions. In the absence of any metals and redox agents, the simple electrolysis system tolerates a variety of primary, secondary, and tertiary alkyl bromides and behaves as an important complement to the directed alkylation of the C(sp2)-H bond and the classic Friedel-Crafts alkylation. This electroreduction process provides a more straightforward, environmentally benign, and effective alkylation method for electron-deficient arenes.
Collapse
Affiliation(s)
- Pufan Ni
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education; Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Lei Yang
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education; Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jiasheng Yang
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education; Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Ruihua Cheng
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Weiping Zhu
- State Key Laboratory of Bioreactor Engineering, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, PR China
| | - Yueyue Ma
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Jinxing Ye
- Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education; Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| |
Collapse
|
45
|
Abstract
Direct borylation of benzylic alcohols has been achieved via an iodine-catalyzed process. This transition-metal-free borylation transformation is compatible with various functional groups and provides a practical and convenient method to access important and useful benzylic boronate esters from widely available benzylic alcohols. Preliminary mechanistic investigations indicated that benzylic iodide and radicals are involved as the key intermediates in this borylation reaction.
Collapse
Affiliation(s)
- Chunyu Yin
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science & Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China
| | - Lu Luo
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science & Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China
| | - Hua Zhang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science & Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China.,Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China
| |
Collapse
|
46
|
Palit K, Sepay N, Panda N. Arylative Methylation of 2,3-Dihydropyrazines and Pyrazinones Using Dimethyl Sulfoxide as a C1 Source. J Org Chem 2023. [PMID: 36786556 DOI: 10.1021/acs.joc.2c02675] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Divergent synthesis of α-C-H methylated pyrazines and pyrazinones using dimethyl sulfoxide as a nonconventional methylating agent under metal-free conditions was reported. Dimethyl sulfoxide-coordinated bromine cation pools generated from the treatment of dimethyl sulfoxide and 1,2-dibromoethane undergo Pummerer-type fragmentation to afford an electrophilic methyl(methylene)sulfonium ion for reaction with a carbon nucleophile followed by aromatization to afford α-methylated pyrazines and pyrazinones.
Collapse
Affiliation(s)
- Kuntal Palit
- Department of Chemistry, National Institute of Technology, Rourkela, Odisha 769008, India
| | - Nayim Sepay
- Department of Chemistry, Lady Brabourne College, Kolkata 700017, India
| | - Niranjan Panda
- Department of Chemistry, National Institute of Technology, Rourkela, Odisha 769008, India
| |
Collapse
|
47
|
Nguyen K, Nguyen V, Tran H, Pham P. Organo-photocatalytic C-H bond oxidation: an operationally simple and scalable method to prepare ketones with ambient air. RSC Adv 2023; 13:7168-7178. [PMID: 36891491 PMCID: PMC9986805 DOI: 10.1039/d3ra00332a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/17/2023] [Indexed: 03/08/2023] Open
Abstract
Oxidative C-H functionalization with O2 is a sustainable strategy to convert feedstock-like chemicals into valuable products. Nevertheless, eco-friendly O2-utilizing chemical processes, which are scalable yet operationally simple, are challenging to develop. Here, we report our efforts, via organo-photocatalysis, in devising such protocols for catalytic C-H bond oxidation of alcohols and alkylbenzenes to ketones using ambient air as the oxidant. The protocols employed tetrabutylammonium anthraquinone-2-sulfonate as the organic photocatalyst which is readily available from a scalable ion exchange of inexpensive salts and is easy to separate from neutral organic products. Cobalt(ii) acetylacetonate was found to be greatly instrumental to oxidation of alcohols and therefore was included as an additive in evaluating the alcohol scope. The protocols employed a nontoxic solvent, could accommodate a variety of functional groups, and were readily scaled to 500 mmol scale in a simple batch setting using round-bottom flasks and ambient air. A preliminary mechanistic study of C-H bond oxidation of alcohols supported the validity of one possible mechanistic pathway, nested in a more complex network of potential pathways, in which the anthraquinone form - the oxidized form - of the photocatalyst activates alcohols and the anthrahydroquinone form - the relevant reduced form of the photocatalyst - activates O2. A detailed mechanism, which reflected such a pathway and was consistent with previously accepted mechanisms, was proposed to account for formation of ketones from aerobic C-H bond oxidation of both alcohols and alkylbenzenes.
Collapse
Affiliation(s)
- Ky Nguyen
- Faculty of Chemistry, University of Science, Vietnam National University Hanoi Vietnam
| | - Van Nguyen
- Faculty of Chemistry, University of Science, Vietnam National University Hanoi Vietnam
| | - Hieu Tran
- Faculty of Chemistry, University of Science, Vietnam National University Hanoi Vietnam
| | - Phong Pham
- Faculty of Chemistry, University of Science, Vietnam National University Hanoi Vietnam
| |
Collapse
|
48
|
Kuhlmann JH, Dickoff JH, Mancheño OG. Visible Light Thiyl Radical-Mediated Desilylation of Arylsilanes. Chemistry 2023; 29:e202203347. [PMID: 36453609 DOI: 10.1002/chem.202203347] [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: 10/27/2022] [Revised: 11/23/2022] [Accepted: 11/30/2022] [Indexed: 12/04/2022]
Abstract
A straightforward, visible-light triggered desilylation of arylsilanes by thiyl radicals is presented. Silyl groups are often used to block a reactive position in multi-step organic synthesis, for which a mild cleavage at a late-stage will provide new possibilities and disconnection routes by CAr -Si cleavage/deprotection. In this work, commercially available and cheap disulfides are employed for the first time in this type of C(sp2 )-Si bond cleavage reactions. Thus, upon irradiation with visible-light, homolytic cleavage of the disulfide give rise to the corresponding thiyl radical that allows for a radical chain mechanism. This methodology represents a mild, fast and simple approach suitable for a broad variety of simply substituted arylsilanes. Moreover, the procedure could be easily extended to natural products and therapeutic derivatives, showing its robustness and synthetic application potential.
Collapse
Affiliation(s)
- Jan H Kuhlmann
- Organic Chemistry Institute, University of Münster, Corrensstraße 36, 48149, Münster, Germany
| | - Jan H Dickoff
- Organic Chemistry Institute, University of Münster, Corrensstraße 36, 48149, Münster, Germany
| | - Olga García Mancheño
- Organic Chemistry Institute, University of Münster, Corrensstraße 36, 48149, Münster, Germany
| |
Collapse
|
49
|
Thakur A, Gupta SS, Dhiman AK, Sharma U. Photoredox Minisci-Type Hydroxyfluoroalkylation of Isoquinolines with N-Trifluoroethoxyphthalimide. J Org Chem 2023; 88:2314-2321. [PMID: 36705295 DOI: 10.1021/acs.joc.2c02726] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A straightforward photocatalytic approach has been demonstrated to incorporate a trifluoroethanol unit onto the isoquinolines. Herein, we report N-trifluoroethoxyphthalimide as a hydroxyfluoroalkyl radical precursor, enabling efficient synthesis of trifluoroethanol-substituted heteroarenes. Radical quenching experiments confirmed the involvement of a free-radical pathway under developed photocatalytic conditions. The DFT calculations confirmed the intramolecular 1,2-HAT reactivity of the O-centered trifluoroethoxy radical (generated from N-trifluoroethoxyphthalimide under photocatalytic condition) to the C-centered trifluoroethanol radical. Fluorescence quenching studies suggested that isoquinoline was responsible for the quenching of Ir-photocatalyst emission. A catalytic cycle involving trifluoroethanol radical reaction with isoquinolines has been proposed.
Collapse
Affiliation(s)
- Ankita Thakur
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource and Technology, Palampur 176061, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shiv Shankar Gupta
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource and Technology, Palampur 176061, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ankit Kumar Dhiman
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource and Technology, Palampur 176061, India
| | - Upendra Sharma
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource and Technology, Palampur 176061, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
50
|
Zhang M, Zhou Q, Luo H, Tang ZL, Xu X, Wang XC. C3-Cyanation of Pyridines: Constraints on Electrophiles and Determinants of Regioselectivity. Angew Chem Int Ed Engl 2023; 62:e202216894. [PMID: 36517651 DOI: 10.1002/anie.202216894] [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: 11/17/2022] [Revised: 12/14/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Methods for C-H cyanation of pyridines are rare. Here, we report a method for C3-selective cyanation of pyridines by a tandem process with the reaction of an in situ generated dihydropyridine with a cyano electrophile as the key step. The method is suitable for late-stage functionalization of pyridine drugs. The low reduction potential of the electrophile and effective transfer of the nitrile group were found to be essential for the success of this method. We studied the reaction mechanism in detail by means of control experiments and theoretical calculations and found that a combination of electronic and steric factors determined the regioselectivity of reactions involving C2-substituted pyridines.
Collapse
Affiliation(s)
- Ming Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Qingyang Zhou
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Heng Luo
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Zi-Lu Tang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Xiufang Xu
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Xiao-Chen Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| |
Collapse
|