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Wang ZX, Xu Y, Gilmour R. Regioselective fluorination of allenes enabled by I(I)/I(III) catalysis. Nat Commun 2024; 15:5770. [PMID: 38982181 PMCID: PMC11233658 DOI: 10.1038/s41467-024-50227-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/02/2024] [Indexed: 07/11/2024] Open
Abstract
The prominence and versatility of propargylic fluorides in medicinal chemistry, coupled with the potency of F/H and F/OH bioisosterism, has created a powerful impetus to develop efficient methods to facilitate their construction. Motivated by the well-established conversion of propargylic alcohols to allenes, an operationally simple, organocatalysis-based strategy to process these abundant unsaturated precursors to propargylic fluorides would be highly enabling: this would consolidate the bioisosteric relationship that connects propargylic alcohols and fluorides. Herein, we describe a highly regioselective fluorination of unactivated allenes based on I(I)/I(III) catalysis in the presence of an inexpensive HF source that serves a dual role as both nucleophile and Brønsted acid activator. This strategy enables a variety of secondary and tertiary propargylic fluorides to be prepared: these motifs are prevalent across the bioactive small molecule spectrum. Facile product derivatisation, concise synthesis of multi-vicinal fluorinated products together with preliminary validation of enantioselective catalysis are disclosed. The expansive potential of this platform is also demonstrated through the highly regioselective organocatalytic oxidation, chlorination and arylation of allenes. It is envisaged that the transformation will find application in molecular design and accelerate the exploration of organofluorine chemical space.
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Affiliation(s)
- Zi-Xuan Wang
- Institute for Organic Chemistry, University of Münster, Corrensstraße 36, 48149, Münster, Germany
| | - Yameng Xu
- Institute for Organic Chemistry, University of Münster, Corrensstraße 36, 48149, Münster, Germany
| | - Ryan Gilmour
- Institute for Organic Chemistry, University of Münster, Corrensstraße 36, 48149, Münster, Germany.
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2
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Alvarez EM, Stewart G, Ullah M, Lalisse R, Gutierrez O, Malapit CA. Site-Selective Electrochemical Arene C-H Amination. J Am Chem Soc 2024; 146:3591-3597. [PMID: 38295054 PMCID: PMC11071122 DOI: 10.1021/jacs.3c11506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Here we present the discovery and development of a highly selective aromatic C-H amination reaction. This electrochemical strategy involves a cathodic reduction process that generates highly electrophilic dicationic N-centered radicals that can efficiently engage in aromatic C-H functionalization and channel the regioselectivity of the aromatic substitution. The nitrogen-radical cation-pi interaction with arenes used throughout nature leads to a charge transfer mechanism, with subsequent aromatic C-N bond formation. This electrochemical process generates aryl DABCOnium salts in excellent yields and regioselectivities (single regioisomer in most cases). The scope of the reaction on arene is broad where various functionalities such as aryl halides (bromides, chlorides, fluorides), carbonyls (ketones, esters, imides), sulfonamides, and heteroarenes (pyridines, bipyridines, and terpyridines) are well tolerated. Moreover, we disclose the synthetic utility of the aryl DABCOnium salt adducts leading to the direct access of diverse aryl piperazines and the chemoselective cleavage of the exocyclic aryl C(sp2)-N bond over electrophilic C(sp3)-N+ bonds via photoredox catalysis to afford synthetically useful aryl radicals that can engage in aryl C-C and C-P bond formation.
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Affiliation(s)
- Eva Maria Alvarez
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
| | - Griffin Stewart
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
| | - Mohammed Ullah
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
| | - Remy Lalisse
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Osvaldo Gutierrez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Christian A Malapit
- Department of Chemistry, Northwestern University, Technological Institute, Evanston, Illinois 60208, United States
- Center for Catalysis and Surface Science, Northwestern University, Evanston, Illinois 60208, United States
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Wang ZX, Livingstone K, Hümpel C, Daniliuc CG, Mück-Lichtenfeld C, Gilmour R. Regioselective, catalytic 1,1-difluorination of enynes. Nat Chem 2023; 15:1515-1522. [PMID: 37845310 PMCID: PMC10624631 DOI: 10.1038/s41557-023-01344-5] [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: 02/22/2023] [Accepted: 09/12/2023] [Indexed: 10/18/2023]
Abstract
Fluorinated small molecules are prevalent across the functional small-molecule spectrum, but the scarcity of naturally occurring sources creates an opportunity for creative endeavour in developing routes to access these important materials. Iodine(I)/iodine(III) catalysis has proven to be particularly well-suited to this task, enabling abundant alkene substrates to be readily intercepted by in situ-generated λ3-iodanes and processed to high-value (di)fluorinated products. These organocatalysis paradigms often emulate metal-based processes by engaging the π bond and, in the case of styrenes, facilitating fluorinative phenonium-ion rearrangements to generate difluoromethylene units. Here we demonstrate that enynes are competent proxies for styrenes, thereby mitigating the recurrent need for aryl substituents, and enabling highly versatile homopropargylic difluorides to be generated in an operationally simple manner. The scope of the method is disclosed, together with application in target synthesis (>30 examples, up to >90% yield).
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Affiliation(s)
- Zi-Xuan Wang
- Institute for Organic Chemistry, Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | - Keith Livingstone
- Institute for Organic Chemistry, Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | - Carla Hümpel
- Institute for Organic Chemistry, Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | - Constantin G Daniliuc
- Institute for Organic Chemistry, Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | | | - Ryan Gilmour
- Institute for Organic Chemistry, Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany.
- Cells in Motion (CiM) Interfaculty Center, Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany.
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Cao H, Histand G, Lin D. Selectfluor-Induced Oxidative Amination of N-Heteroaromatics with Purine. J Org Chem 2023; 88:5687-5695. [PMID: 37120834 DOI: 10.1021/acs.joc.3c00149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
An oxidative coupling reaction between purines and aromatic N-heterocycles was developed to synthesize a series of N-heteroaryl purine derivatives using Selectfluor as an oxidant at room temperature. This process uses a commercial oxidant, uses no base, metal, or other additives, is simple to carry out, and has a broad range of substrates.
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Affiliation(s)
- Haiyan Cao
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong 510641, China
| | - Gary Histand
- The International School of Advanced Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510640, China
| | - Dongen Lin
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong 510641, China
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Dağalan Z, Koçak R, Daştan A, Nişancı B. Selectfluor and TBAX (Cl, Br) Mediated Oxidative Chlorination and Bromination of Olefins. Org Lett 2022; 24:8261-8264. [PMID: 36129307 PMCID: PMC9680025 DOI: 10.1021/acs.orglett.2c02627] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Herein, we report
the first metal-free and molecular halogen reagent-free
dihomohalogenation methodology by using Selectfluor as an oxidant
and tetrabutylammonium bromide/chloride salts as a halogen source.
This effective strategy provides various fluorine-free halogenated
products easily in quantitative yields from alkenes, alkynes, and
natural products.
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Affiliation(s)
- Ziya Dağalan
- Department of Chemistry, Faculty of Sciences, Ataturk University, Erzurum 25240, Turkey
| | - Ramazan Koçak
- Department of Chemistry, Faculty of Sciences, Ataturk University, Erzurum 25240, Turkey
| | - Arif Daştan
- Department of Chemistry, Faculty of Sciences, Ataturk University, Erzurum 25240, Turkey
| | - Bilal Nişancı
- Department of Chemistry, Faculty of Sciences, Ataturk University, Erzurum 25240, Turkey
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Selectfluor Mediated Difunctionalization of Olefins towards the Synthesis of Fluoromethylated Morpholines. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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