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Choi A, Das A, Meijer AJHM, Proietti Silvestri I, Coldham I. Synthesis of enantioenriched spirocyclic 2-arylpiperidines via kinetic resolution. Org Biomol Chem 2024; 22:1602-1607. [PMID: 38314915 DOI: 10.1039/d4ob00011k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Kinetic resolution of N-Boc-spirocyclic 2-arylpiperidines with spiro substitution at C-4 was achieved with high enantiomeric ratios using the chiral base n-BuLi/sparteine. Cyclopropanation or metallaphotoredox catalysis were used to access the piperidines, which could be further functionalised without loss of enantiopurity, highlighting their use as potential 3D fragments for drug discovery.
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Affiliation(s)
- Anthony Choi
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
| | - Anjan Das
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
| | | | | | - Iain Coldham
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
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2
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Sirvinskaite G, Nardo CS, Müller P, Gasser AC, Morandi B. Direct Synthesis of Unprotected Indolines Through Intramolecular sp 3 C-H Amination Using Nitroarenes as Aryl Nitrene Precursors. Chemistry 2023; 29:e202301978. [PMID: 37404217 DOI: 10.1002/chem.202301978] [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: 06/28/2023] [Revised: 07/03/2023] [Accepted: 07/03/2023] [Indexed: 07/06/2023]
Abstract
Given the prevalence of molecules containing nitro groups in organic synthesis, innovative methods to expand the reactivity of this functional group are of interest in both industrial and academic settings. In this report, a metal-free intramolecular benzylic sp3 C-H amination is disclosed using aryl nitro compounds as aryl nitrene precursors. Organosilicon reagent N,N'-bis(trimethylsilyl)-4,4'-bipyridinylidene (Si-DHBP) served as an efficient reductant in the transformation, enabling the in situ generation of aryl nitrene species for the direct, metal-free synthesis of unprotected 2-arylindolines from the corresponding nitroarene compounds.
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Affiliation(s)
- Giedre Sirvinskaite
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Celine S Nardo
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Patrick Müller
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Aurelio C Gasser
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Bill Morandi
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
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3
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Yeo S, Choi A, Greaves S, Meijer AJHM, Silvestri IP, Coldham I. Kinetic Resolution of 2-Aryldihydroquinolines Using Lithiation - Synthesis of Chiral 1,2- and 1,4-Dihydroquinolines. Chemistry 2023; 29:e202300815. [PMID: 37067465 PMCID: PMC10946909 DOI: 10.1002/chem.202300815] [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: 03/14/2023] [Revised: 04/12/2023] [Accepted: 04/17/2023] [Indexed: 04/18/2023]
Abstract
Highly enantiomerically enriched dihydrohydroquinolines were prepared in two steps from quinoline. Addition of aryllithiums to quinoline with tert-butoxycarbonyl (Boc) protection gave N-Boc-2-aryl-1,2-dihydroquinolines. These were treated with n-butyllithium and electrophilic trapping occurred exclusively at C-4 of the dihydroquinoline, a result supported by DFT studies. Variable temperature NMR spectroscopy gave kinetic data for the barrier to rotation of the carbonyl group (ΔG≠ ≈49 kJ mol-1 , 195 K). Lithiation using the diamine sparteine allowed kinetic resolutions with high enantioselectivities (enantiomer ratio up to 99 : 1). The enantioenriched 1,2-dihydroquinolines could be converted to 1,4-dihydroquinolines with retention of stereochemistry. Further functionalisation led to trisubstituted products. Reduction provided enantioenriched tetrahydroquinolines, whereas acid-promoted removal of Boc led to quinolines, and this was applied to a synthesis of the antimalarial compound M5717.
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Affiliation(s)
- Song‐Hee Yeo
- Department of ChemistryUniversity of SheffieldBrook HillSheffieldS3 7HFUK
| | - Anthony Choi
- Department of ChemistryUniversity of SheffieldBrook HillSheffieldS3 7HFUK
| | - Sophie Greaves
- Department of ChemistryUniversity of SheffieldBrook HillSheffieldS3 7HFUK
| | | | | | - Iain Coldham
- Department of ChemistryUniversity of SheffieldBrook HillSheffieldS3 7HFUK
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4
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Das A, Choi A, Coldham I. Photocatalysis and Kinetic Resolution by Lithiation to Give Enantioenriched 2-Arylpiperazines. Org Lett 2023; 25:987-991. [PMID: 36735675 PMCID: PMC9942196 DOI: 10.1021/acs.orglett.3c00074] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Piperazines are important heterocycles in drug compounds. We report the asymmetric synthesis of arylpiperazines by photocatalytic decarboxylative arylation (metallaphotoredox catalysis) then kinetic resolution using n-BuLi/(+)-sparteine. This gave a range of piperazines with very high enantioselectivities. Further functionalizations gave enantioenriched 2,2-disubstituted piperazines, and either N-substituent can be removed selectively. Late-stage functionalizations of enantioenriched piperazine derivatives were demonstrated, including synthesis of a drug compound with glycogen synthase kinase (GSK)-3β inhibitor activity with potential for treating Alzheimer's disease.
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5
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Choi A, Meijer AJHM, Silvestri IP, Coldham I. Kinetic Resolution of 2-Aryl-4-methylenepiperidines toward Enantioenriched Functionalizable Piperidine Fragments. J Org Chem 2022; 87:8819-8823. [PMID: 35699313 PMCID: PMC9490820 DOI: 10.1021/acs.joc.2c00862] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
![]()
The
base n-BuLi with sparteine allows a kinetic
resolution of N-Boc-2-aryl-4-methylenepiperidines.
The 2,2-disubstituted products and recovered starting materials were
isolated with high enantiomeric ratios. From VT-NMR spectroscopy and
DFT studies, the rate of rotation of the N-Boc group
is fast. Lithiation and trapping of the enantioenriched starting materials
gave 2,2-disubstituted piperidines with retention of stereochemistry.
Functionalization of the 4-methylene group led to a variety of 2,4-disubstituted
piperidines without loss of enantiopurity that could be useful building
blocks for drug discovery.
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Affiliation(s)
- Anthony Choi
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Anthony J H M Meijer
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | | | - Iain Coldham
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
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6
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Liu C, Wang M, Xu Y, Li Y, Liu Q. Manganese-Catalyzed Asymmetric Hydrogenation of 3H-Indoles. Angew Chem Int Ed Engl 2022; 61:e202202814. [PMID: 35238455 DOI: 10.1002/anie.202202814] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Indexed: 12/21/2022]
Abstract
The asymmetric hydrogenation (AH) of 3H-indoles represents an ideal approach to the synthesis of useful chiral indoline scaffolds. However, very few catalytic systems based on precious metals have been developed to realize this challenging reaction. Herein, we report a Mn-catalyzed AH of 3H-indoles with excellent yields and enantioselectivities. The kinetic resolution of racemic 3H-indoles by AH was also achieved with high s-factors to construct quaternary stereocenters. Many acid-sensitive functional groups, which cannot be tolerated when using a state-of-the-art ruthenium catalyst, were compatible with manganese catalysis. This new process expands the scope of this transformation and highlights the uniqueness of earth-abundant metal catalysis. The reaction could proceed with catalyst loadings at the parts per million (ppm) level with an exceptional turnover number of 72 350. This is the highest value yet reported for an earth-abundant metal-catalyzed AH reaction.
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Affiliation(s)
- Chenguang Liu
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Mingyang Wang
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yihan Xu
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yibiao Li
- School of Biotechnology and Health, Wuyi University, Jiangmen, Guangdong, 529090, China
| | - Qiang Liu
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
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Liu C, Wang M, Xu Y, Li Y, Liu Q. Manganese‐Catalyzed Asymmetric Hydrogenation of 3H‐Indoles. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | | | - Yihan Xu
- Tsinghua University Department of Chemistry CHINA
| | - Yibiao Li
- Wuyi University Department of Chemistry CHILE
| | - Qiang Liu
- Tsinghua University Department of Chemistry Tsinghuayuan 1 100084 Beijing CHINA
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8
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Coldham I, El-Tunsi A, Carter N, Yeo SH, Priest JD, Choi A, Kobras CM, Ndlovu S, Proietti Silvestri I, Fenton AK. Kinetic Resolution by Lithiation: Highly Enantioselective Synthesis of Substituted Dihydrobenzoxazines and Tetrahydroquinoxalines. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1638-2478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AbstractKinetic resolution provided a highly enantioselective method to access a range of 3-aryl-3,4-dihydro-2H-1,4-benzoxazines using n-butyllithium and the chiral ligand sparteine. The enantioenrichment remained high on removing the tert-butoxycarbonyl (Boc) protecting group. The intermediate organolithium undergoes ring opening to an enamine. The kinetic resolution was extended to give enantiomerically enriched substituted 1,2,3,4-tetrahydroquinoxalines and was applied to the synthesis of an analogue of the antibiotic levofloxacin that was screened for its activity against the human pathogen Streptococcus pneumoniae.
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Affiliation(s)
- Iain Coldham
- Department of Chemistry, University of Sheffield
| | | | | | - Song-Hee Yeo
- Department of Chemistry, University of Sheffield
| | | | - Anthony Choi
- Department of Chemistry, University of Sheffield
| | - Carolin M. Kobras
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield
| | | | | | - Andrew K. Fenton
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield
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