1
|
Zahara AJ, Haines BE, Wilkerson-Hill SM. Programmed Heterocycle Synthesis Using Halomucononitriles as Pyridinimine Precursors. Org Lett 2024; 26:2976-2981. [PMID: 38557087 DOI: 10.1021/acs.orglett.4c00547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Herein we report a method to convert primary amines, ubiquitous motifs found in pharmaceutical libraries, to either imidazo[1,2-a]pyridines or 7-alkyl azaindoles in two steps from known compounds. Using halomucononitrile reagents, we can directly access 5-bromo-6-imino-1-alkyl-1,6-dihydropyridine-2-carbonitriles (pyridinimines) in a single step from primary amines (25-93% yield) through the cyclization of transient aminomucononitrile intermediates. We then demonstrate that these compounds can be readily converted to 7-alkylazaindoles using Sonogashira cross-coupling conditions (13 examples, up to 91% yield). Under oxidative conditions, the pyridinimines serve as directing groups for C-H functionalization reactions to afford imidazo[1,2-a]pyridines. We also studied the mechanism of the cyclization event using DFT calculations and propose that this takes place via sequential base-mediated E/Z isomerization and cyclization steps.
Collapse
Affiliation(s)
- Adam J Zahara
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Brandon E Haines
- Department of Chemistry, Westmont College, Santa Barbara, California 93108, United States
| | - Sidney M Wilkerson-Hill
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| |
Collapse
|
2
|
Bazzoni M, Lhoste C, Bonnet J, Konan KE, Bernard A, Giraudeau P, Felpin FX, Dumez JN. In-line Multidimensional NMR Monitoring of Photochemical Flow Reactions. Chemistry 2023; 29:e202203240. [PMID: 36651473 DOI: 10.1002/chem.202203240] [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: 10/17/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
This work demonstrates the in-line monitoring of a flow photochemical reaction using 1D and ultrafast 2D NMR methods at high magnetic field. The reaction mixture exiting the flow reactor is flown through the NMR spectrometer and directly analyzed. In the case of simple substrates, suitable information can be obtained through 1D 1 H spectra, but for molecules of higher complexity the use of 2D experiments is key to address signal overlaps and assignment issues. Here we show the usefulness of ultrafast 2D COSY experiments acquired in 70 s or less, for the in-line monitoring of photochemical reactions, and the possibility to obtain reliable quantitative information. This is a powerful framework to, for example, efficiently screen reaction conditions.
Collapse
Affiliation(s)
| | - Célia Lhoste
- Nantes Université, CNRS, CEISAM UMR6230, F-4400, Nantes, France
| | - Justine Bonnet
- Nantes Université, CNRS, CEISAM UMR6230, F-4400, Nantes, France
| | | | - Aurélie Bernard
- Nantes Université, CNRS, CEISAM UMR6230, F-4400, Nantes, France
| | | | | | | |
Collapse
|
3
|
Shee M, Singh NDP. Photogenerated Azido Radical Mediated Oxidation: Access to Carbonyl Functionality from Alcohols, Alkylarenes, and Olefins via Organophotoredox. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Maniklal Shee
- Department of Chemistry Indian Institute of Technology Kharagpur 721302 Kharagpur West Bengal India
| | - N. D. Pradeep Singh
- Department of Chemistry Indian Institute of Technology Kharagpur 721302 Kharagpur West Bengal India
| |
Collapse
|
4
|
Zheng J, Tang N, Xie H, Breit B. Regio-, Diastereo-, and Enantioselective Decarboxylative Hydroaminoalkylation of Dienol Ethers Enabled by Dual Palladium/Photoredox Catalysis. Angew Chem Int Ed Engl 2022; 61:e202200105. [PMID: 35170841 PMCID: PMC9314026 DOI: 10.1002/anie.202200105] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Indexed: 12/15/2022]
Abstract
Intermolecular photocatalytic hydroaminoalkylation (HAA) of alkenes have emerged as a powerful method for the construction of alkyl amines. Although there are some studies aiming at stereoselective photocatalytic HAA reactions, the alkenes are limited to electrophilic alkenes. Herein, we report a highly regio‐, diastereo‐, and enantioselective HAA of electron‐rich dienol ethers and α‐amino radicals derived from α‐amino acids using a unified photoredox and palladium catalytic system. This decarboxylative 1,2‐Markovnikov addition enables the construction of vicinal amino tertiary ethers with high levels of regio‐ (up to >19 : 1 rr), diastereo‐ (up to >19 : 1 dr), and enantioselectivity control (up to >99 % ee). Mechanistic studies support a reversible hydropalladation as a key step.
Collapse
Affiliation(s)
- Jun Zheng
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg im Breisgau, Germany
| | - Nana Tang
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg im Breisgau, Germany
| | - Hui Xie
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg im Breisgau, Germany
| | - Bernhard Breit
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg im Breisgau, Germany
| |
Collapse
|
5
|
Zheng J, Tang N, Xie H, Breit B. Regio‐, Diastereo‐, and Enantioselective Decarboxylative Hydro‐aminoalkylation of Dienol Ethers Enabled by Dual Palladium/Pho‐toredox Catalysis. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jun Zheng
- Institut für Organische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg im Breisgau Germany
| | - Nana Tang
- Institut für Organische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg im Breisgau Germany
| | - Hui Xie
- Institut für Organische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg im Breisgau Germany
| | - Bernhard Breit
- Institut für Organische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg im Breisgau Germany
| |
Collapse
|
6
|
Maitland JAP, Leitch JA, Yamazaki K, Christensen KE, Cassar DJ, Hamlin TA, Dixon DJ. Switchable, Reagent‐Controlled Diastereodivergent Photocatalytic Carbocyclisation of Imine‐Derived α‐Amino Radicals. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- J. Andrew P. Maitland
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Jamie A. Leitch
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
- Current address: Department of Pharmaceutical and Biological Chemistry UCL (University College London) School of Pharmacy 29–39 Brunswick Square London WC1N 1AX UK
| | - Ken Yamazaki
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
- Department of Theoretical Chemistry Amsterdam Institute of Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM) Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands
| | - Kirsten E. Christensen
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | | | - Trevor A. Hamlin
- Department of Theoretical Chemistry Amsterdam Institute of Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM) Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands
| | - Darren J. Dixon
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| |
Collapse
|
7
|
Maitland JAP, Leitch JA, Yamazaki K, Christensen KE, Cassar DJ, Hamlin TA, Dixon DJ. Switchable, Reagent-Controlled Diastereodivergent Photocatalytic Carbocyclisation of Imine-Derived α-Amino Radicals. Angew Chem Int Ed Engl 2021; 60:24116-24123. [PMID: 34449968 PMCID: PMC8597041 DOI: 10.1002/anie.202107253] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/13/2021] [Indexed: 12/15/2022]
Abstract
A reagent‐controlled stereodivergent carbocyclisation of aryl aldimine‐derived, photocatalytically generated, α‐amino radicals possessing adjacent conjugated alkenes, affording either bicyclic or tetracyclic products, is described. Under net reductive conditions using commercial Hantzsch ester, the α‐amino radical species underwent a single stereoselective cyclisation to give trans‐configured amino‐indane structures in good yield, whereas using a substituted Hantzsch ester as a milder reductant afforded cis‐fused tetracyclic tetrahydroquinoline frameworks, resulting from two consecutive radical cyclisations. Judicious choice of the reaction conditions allowed libraries of both single and dual cyclisation products to be synthesised with high selectivity, notable predictability, and good‐to‐excellent yields. Computational analysis employing DFT revealed the reaction pathway and mechanistic rationale behind this finely balanced yet readily controlled photocatalytic system.
Collapse
Affiliation(s)
- J Andrew P Maitland
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Jamie A Leitch
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.,Current address: Department of Pharmaceutical and Biological Chemistry, UCL (University College London), School of Pharmacy, 29-39 Brunswick Square, London, WC1N 1AX, UK
| | - Ken Yamazaki
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.,Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
| | - Kirsten E Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | | | - Trevor A Hamlin
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
| | - Darren J Dixon
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| |
Collapse
|
8
|
Zhao H, Leonori D. Minimization of Back-Electron Transfer Enables the Elusive sp 3 C-H Functionalization of Secondary Anilines. Angew Chem Int Ed Engl 2021; 60:7669-7674. [PMID: 33459469 PMCID: PMC8048505 DOI: 10.1002/anie.202100051] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 01/14/2021] [Indexed: 02/02/2023]
Abstract
Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C-H functionalization.
Collapse
Affiliation(s)
- Huaibo Zhao
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | - Daniele Leonori
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| |
Collapse
|
9
|
Zhao H, Leonori D. Minimization of Back‐Electron Transfer Enables the Elusive sp
3
C−H Functionalization of Secondary Anilines. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Huaibo Zhao
- Department of Chemistry University of Manchester Oxford Road Manchester M13 9PL UK
| | - Daniele Leonori
- Department of Chemistry University of Manchester Oxford Road Manchester M13 9PL UK
| |
Collapse
|
10
|
Paul A, Kim JH, Daniel SD, Seidel D. Diversification of Unprotected Alicyclic Amines by C-H Bond Functionalization: Decarboxylative Alkylation of Transient Imines. Angew Chem Int Ed Engl 2021; 60:1625-1628. [PMID: 32975859 PMCID: PMC7854982 DOI: 10.1002/anie.202011641] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/24/2020] [Indexed: 12/13/2022]
Abstract
Despite extensive efforts by many practitioners in the field, methods for the direct α-C-H bond functionalization of unprotected alicyclic amines remain rare. A new advance in this area utilizes N-lithiated alicyclic amines. These readily accessible intermediates are converted to transient imines through the action of a simple ketone oxidant, followed by alkylation with a β-ketoacid under mild conditions to provide valuable β-amino ketones with unprecedented ease. Regioselective α'-alkylation is achieved for substrates with existing α-substituents. The method is further applicable to the convenient one-pot synthesis of polycyclic dihydroquinolones through the incorporation of a SN Ar step.
Collapse
Affiliation(s)
- Anirudra Paul
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
| | - Jae Hyun Kim
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
- Current address: College of Pharmacy, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Scott D Daniel
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
| | - Daniel Seidel
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
| |
Collapse
|
11
|
Paul A, Kim JH, Daniel SD, Seidel D. Diversification of Unprotected Alicyclic Amines by C−H Bond Functionalization: Decarboxylative Alkylation of Transient Imines. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202011641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Anirudra Paul
- Center for Heterocyclic Compounds, Department of Chemistry University of Florida Gainesville FL 32611 USA
| | - Jae Hyun Kim
- Center for Heterocyclic Compounds, Department of Chemistry University of Florida Gainesville FL 32611 USA
- Current address: College of Pharmacy Kangwon National University Chuncheon 24341 Republic of Korea
| | - Scott D. Daniel
- Center for Heterocyclic Compounds, Department of Chemistry University of Florida Gainesville FL 32611 USA
| | - Daniel Seidel
- Center for Heterocyclic Compounds, Department of Chemistry University of Florida Gainesville FL 32611 USA
| |
Collapse
|