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Sekar P, Gupta A, English LE, Rabbitt CE, Male L, Jupp AR, Davies PW. Regiodivergent Synthesis of 4- and 5-Sulfenyl Oxazoles from Alkynyl Thioethers. Chemistry 2024; 30:e202401465. [PMID: 38743746 DOI: 10.1002/chem.202401465] [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: 04/15/2024] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 05/16/2024]
Abstract
The regiodivergent synthesis of 4- and 5-sulfenyl oxazoles from 1,4,2-dioxazoles and alkynyl thioethers has been achieved. Gold-catalysed conditions are used to favour the formation of 5-sulfenyl oxazoles via β-selective attack of the nitrenoid relative to the sulfenyl group. In contrast, 4-sulfenyl oxazoles are formed by α-selective reaction under Brønsted acid conditions from the same substrates. The nature of stabilising gold-sulfur interactions have been investigated by natural bond orbital analysis, showing that the S→Au interactions are significantly stronger in the intermediate that favours the 5-sulfenyl oxazoles. A kinetic survey identifies catalyst inhibition processes. This study into the regiodivergent methods includes the development of telescoped annulation-oxidation protocols for regioselective access to oxazole sulfoxides and sulfones.
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Affiliation(s)
- Prakash Sekar
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Aniket Gupta
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Laura E English
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Clare E Rabbitt
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Louise Male
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Andrew R Jupp
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Paul W Davies
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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2
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Huang M, Sun H, Seufert F, Friedrich A, Marder TB, Hu J. Photoredox/Cu-Catalyzed Decarboxylative C(sp 3)-C(sp 3) Coupling to Access C(sp 3)-Rich gem-Diborylalkanes. Angew Chem Int Ed Engl 2024:e202401782. [PMID: 38818649 DOI: 10.1002/anie.202401782] [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: 01/25/2024] [Revised: 05/28/2024] [Accepted: 05/28/2024] [Indexed: 06/01/2024]
Abstract
gem-Diborylalkanes are highly valuable building blocks in organic synthesis and pharmaceutical chemistry due to their ability to participate in multi-step cross-coupling transformations, allowing for the rapid generation of molecular complexity. While progress has been made in their synthetic metholodology, the construction of β-tertiary and C(sp3)-rich gem-diborylalkanes remains a synthetic challenge due to substrate limitations and steric hindrance issues. An approach is presented that utilizes synergistic photoredox and copper catalysis to achieve efficient C(sp3)-C(sp3) cross-coupling of alkyl N-hydroxyphthalimide esters, which can easily be obtained from alkyl carboxylic acids, with diborylmethyl species, providing a series of C(sp3)-rich gem-diborylalkanes with 1°, 2°, and even 3° β positions. Furthermore, this approach can also be applied to complex medicinal compounds and natural products, offering rapid access to molecular complexity and late-stage functionalization of C(sp3)-rich drug candidates. Mechanistic experiments revealed that diborylmethyl Cu(I) species participated in both the photoredox process and the key C(sp3)-C(sp3) bond-forming step.
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Affiliation(s)
- Mingming Huang
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Huaxing Sun
- State Key Laboratory of Organic Electronics and Information Displays & & Institute of Advanced Materials (IAM), College of Chemistry and Life Sciences, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Florian Seufert
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Alexandra Friedrich
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Todd B Marder
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jiefeng Hu
- State Key Laboratory of Organic Electronics and Information Displays & & Institute of Advanced Materials (IAM), College of Chemistry and Life Sciences, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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3
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Huang B, Xing D, Jiang H, Huang L. Lewis Acid-Catalyzed Formal [4 + 2] Reaction of Alkynyl Sulfides and 2-Pyrones To Access Polysubstituted Aryl Sulfides. J Org Chem 2024; 89:7280-7285. [PMID: 38716567 DOI: 10.1021/acs.joc.4c00288] [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
A practical and efficient method to access polysubstituted aryl sulfides has been discovered via a Lewis acid-catalyzed reaction between alkynyl sulfide and 2-pyrone, involving a Diels-Alder/retro-Diels-Alder pathway. Alkynyl sulfide as an electron-rich dienophile and 2-pyrones as electron-poor dienes are conjunctively transformed into a series of polysubstituted aryl sulfides with broad functional group compatibility in good to excellent yields (40 examples, 43-88% yield). The robustness and practicality of the protocol has been demonstrated through gram-scale synthesis and the ease of transformation of the resulting products.
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Affiliation(s)
- Bin Huang
- State Key Laboratory of Pulp and Paper Engineering, Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Donghui Xing
- State Key Laboratory of Pulp and Paper Engineering, Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Huanfeng Jiang
- State Key Laboratory of Pulp and Paper Engineering, Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Liangbin Huang
- State Key Laboratory of Pulp and Paper Engineering, Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
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Fernández E. α-Boryl Carbanions: The Influence of Geminal Heteroatoms in C-C Bond Formation. CHEM REC 2024; 24:e202300349. [PMID: 38308376 DOI: 10.1002/tcr.202300349] [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: 11/17/2023] [Revised: 01/12/2024] [Indexed: 02/04/2024]
Abstract
The wide applications of alpha-boryl carbanions in selective coupling with organohalides, imines/carbonyls and conjugated unsaturated substrates has become an interesting tool for organic synthesis. Strategically, the inclusion of heteroatoms, such as Si, S, N, F, Cl, Br and I in the alpha position opens a new venue towards multifunctionalities in molecular design. Here, a conceptual and practical view on powerful carbanions, containing α-silicoboron, α-thioboron, α-haloboron and α-aminoboron is given, as well as a prespective on their efficient application for selective electrophilic trapping.
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Affiliation(s)
- Elena Fernández
- Dept. Química Física i Inorgànica, University Rovira i Virgili, Tarragona, Spain
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Ning PF, Wei Y, Chen XY, Yang YF, Gao FC, Hong K. A General Method to Access Sterically Encumbered Geminal Bis(boronates) via Formal Umpolung Transformation of Terminal Diboron Compounds. Angew Chem Int Ed Engl 2024; 63:e202315232. [PMID: 38059757 DOI: 10.1002/anie.202315232] [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: 10/10/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023]
Abstract
General methods for the preparation of geminal bis(boronates) are of great interest due to their widespread applications in organic synthesis. While the terminal gem-diboron compounds are readily accessible, the construction of the sterically encumbered, internal analogues has remained a prominent challenge. Herein, we report a formal umpolung strategy to access these valuable building blocks. The readily available 1,1-diborylalkanes were first converted into the corresponding α-halogenated derivatives, which then serve as electrophilic components, undergoing a formal substitution with a diverse array of nucleophiles to form a series of C-C, C-O, C-S, and C-N bonds. This protocol features good tolerance to steric hindrance and a wide variety of functional groups and heterocycles. Notably, this strategy can also be extended to the synthesis of diaryl and terminal gem-diboron compounds, therefore providing a general approach to various types of geminal bis(boronates).
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Affiliation(s)
- Peng-Fei Ning
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China
| | - Yi Wei
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China
| | - Xin-Yi Chen
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China
| | - Yi-Fei Yang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China
| | - Feng-Chen Gao
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China
| | - Kai Hong
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China
- Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China
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6
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Fang T, Wang L, Wu M, Qi X, Liu C. Diborodichloromethane as Versatile Reagent for Chemodivergent Synthesis of gem-Diborylalkanes. Angew Chem Int Ed Engl 2024; 63:e202315227. [PMID: 38059834 DOI: 10.1002/anie.202315227] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023]
Abstract
The development of boron reagents is crucial for synthetic chemistry. Herein, we present a scalable and practical synthesis of diborodichloromethane (DBDCM) through the reaction of trichloromethyllithium with bis(pinacolato)diboron (B2 pin2 ). The resulting DBDCM reagent serves as a basic synthetic unit for the construction of various structurally diverse gem-diborylalkanes through controllable C-Cl functionalizations. Moreover, we have developed consecutive tetra-functionalizations of DBDCM for the construction of diverse tertiary and quaternary carbon containing molecules. The use of isotopically enriched 13 C-chloroform and 10 B2 pin2 enables the synthesis of isotopically enriched 13 C-DBDCM and 10 B-DBDCM reagents, which are beneficial for the convenient synthesis of carbon-13 and boron-10 molecules.
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Affiliation(s)
- Tongchang Fang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 730000, Lanzhou, P. R. China
- University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| | - Liwei Wang
- College of Chemistry and Molecular Sciences, Wuhan University, 430072, Wuhan, P. R. China
| | - Miaomiao Wu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 730000, Lanzhou, P. R. China
| | - Xiaotian Qi
- College of Chemistry and Molecular Sciences, Wuhan University, 430072, Wuhan, P. R. China
| | - Chao Liu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 730000, Lanzhou, P. R. China
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Su X, Wang Y, Feng Q, Sun J. Heterodifunctionalization of Electron-Rich Alkynes Catalyzed by in Situ Generated Silylium Ions. Org Lett 2024; 26:421-426. [PMID: 38166166 DOI: 10.1021/acs.orglett.3c04208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Silylium ions are versatile Lewis acids in organic synthesis. While they have been well-known for the activation of σ donors, catalysis initiated by the activation of π donors remains underdeveloped, particularly for alkynes. Herein, we demonstrate an example of silylium-catalyzed alkyne heterodifunctionalization. The silylium ion generated in situ from HNTf2 and the silyl reagent serve as superior catalysts in the efficient silylphosphination and silylcyanation of electron-rich alkynes with excellent regio- and stereoselectivity. The compatibility of this protocol with strongly coordinating ligands (Ph2P and CN) not only complements the metal-catalyzed systems but also expands the scope of silylium-catalyzed reactions.
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Affiliation(s)
- Xiang Su
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Yong Wang
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, China
| | - Qiang Feng
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, China
| | - Jianwei Sun
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, China
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Sun Y, Song N, Han Y, Ding S. Organic Base-Facilitated Thiol-Thioalkyne Reaction with Exclusive Regio- and Stereoselectivity. J Org Chem 2023; 88:15130-15141. [PMID: 37877589 DOI: 10.1021/acs.joc.3c01621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Here, we report the regiospecific hydrothiolation of electron-rich thioalkynes with exclusive stereoselectivity facilitated by an organic base, which could proceed exceedingly fast under ambient atmosphere and room temperature, affording β trans addition products in up to nearly quantitative yields. The dual nature of the sulfur atom in attracting and donating electrons is supposed to be pivotal in determining the regio- and stereoselectivity. This system tolerates a wide range of thiols and thioalkynes and shows great potential in polymer synthesis.
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Affiliation(s)
- Yunxin Sun
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Ningning Song
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yanchen Han
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shengtao Ding
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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9
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Li Y, Chen Z, Lin S, Liu Y, Qian J, Li Q, Huang Z, Wang H. Regioselective Electrophilic Addition to Propargylic B(MIDA)s Enabled by β-Boron Effect. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2304282. [PMID: 37632709 PMCID: PMC10602563 DOI: 10.1002/advs.202304282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Indexed: 08/28/2023]
Abstract
Electrophilic addition reaction to alkynes is of fundamental importance in organic chemistry, yet the regiocontrol when reacting with unsymmetrical 1,2-dialkyl substituted alkynes is often problematic. Herein, it is demonstrated that the rarely recognized β-boron effect can confer a high level of site-selectivity in several alkyne electrophilic addition reactions. A broad range of highly functionalized and complex organoborons are thus formed under simple reaction conditions starting from propargylic MIDA (N-methyliminodiacetic acid) boronates. These products are demonstrated to be valuable building blocks in organic synthesis. In addition to the regiocontrol, this study also observes a drastic rate enhancement upon B(MIDA) substitution. Theoretical calculation reveals that the highest occupied molecular obital (HOMO) energy level of propargylic B(MIDA) is significantly raised by 0.3 eV, and the preferential electrophilic addition to the γ position is due to its higher HOMO orbital coefficient and more negative natural bond orbital (NBO) charge compared to the β position. This study demonstrates the potential of utilizing the β-boron effect in stereoelectronic control of chemical transformations, which can inspire further research in this area.
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Affiliation(s)
- Yin Li
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
| | - Zhi‐Hao Chen
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
| | - Shuang Lin
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
| | - Yuan Liu
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
| | - Jiasheng Qian
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
| | - Qingjiang Li
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
| | - Zhi‐Shu Huang
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
| | - Honggen Wang
- Guangdong Key Laboratory of Chiral Molecule and Drug DiscoverySchool of Pharmaceutical SciencesSun Yat‐Sen UniversityGuangzhou510006China
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