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Choi A, El‐Tunsi A, Wang Y, Meijer AJHM, Li J, Li X, Proietti Silvestri I, Coldham I. Asymmetric Synthesis of 2-Arylindolines and 2,2-Disubstituted Indolines by Kinetic Resolution. Chemistry 2021; 27:11670-11675. [PMID: 34110662 PMCID: PMC8456874 DOI: 10.1002/chem.202101248] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 01/18/2023]
Abstract
Kinetic resolution of 2-arylindolines (2,3-dihydroindoles) was achieved by treatment of their N-tert-butoxycarbonyl (Boc) derivatives with n-butyllithium and sparteine in toluene at -78 °C followed by electrophilic quench. The unreacted starting materials together with the 2,2-disubstituted products could be isolated with high enantiomer ratios. Variable temperature NMR spectroscopy showed that the rate of Boc rotation was fast (ΔG≠ ≈57 kJ/mol at 195 K). This was corroborated by DFT studies and by in situ ReactIR spectroscopy. The enantioenriched N-Boc-2-arylindolines were converted to 2,2-disubstituted products without significant loss in enantiopurity. Hence, either enantiomer of the 2,2-disubstituted products could be obtained with high selectivity from the same enantiomer of the chiral ligand sparteine (one from the kinetic resolution and the other from subsequent lithiation-trapping of the recovered starting material). Secondary amine products were prepared by removing the Boc group with acid to provide a way to access highly enantioenriched 2-aryl and 2,2-disubstituted indolines.
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Affiliation(s)
- Anthony Choi
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
| | - Ashraf El‐Tunsi
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
| | - Yuhang Wang
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
| | | | - Jia Li
- School of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi'an710062PR China
| | - Xiabing Li
- School of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi'an710062PR China
| | | | - Iain Coldham
- Department of ChemistryUniversity of Sheffield Brook HillSheffieldS3 7HFUK
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Torralvo H, Albert J, Ariza X, Font-Bardia M, Garcia J, Granell J, Martinez M. Pyridine- and Quinoline-Derived Imines as N, N-Bidentate Directing Groups in Palladium versus Platinum C–H Bond Activation Reactions. Organometallics 2021. [DOI: 10.1021/acs.organomet.0c00703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Héctor Torralvo
- Departament de Química Inorgànica i Orgànica, Secció de Química Orgànica i Institut de Biomedicina (IBUB), Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Joan Albert
- Departament de Química Inorgànica i Orgànica, Secció de Química Inorgànica, Facultat de Quimica, Universitat de Barcelona, Martí i Franquès 1-11. 08028 Barcelona, Spain
| | - Xavier Ariza
- Departament de Química Inorgànica i Orgànica, Secció de Química Orgànica i Institut de Biomedicina (IBUB), Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
| | - Mercè Font-Bardia
- Unitat de Difracció de Raigs-X., Centre Científic i Tecnològ̀ic de la Universitat de Barcelona, Universitat de Barcelona, Solé i Sabarís1-3, 08028 Barcelona, Spain
- Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Martí i Franquès s/n, 08028 Barcelona, Spain
| | - Jordi Garcia
- Departament de Química Inorgànica i Orgànica, Secció de Química Orgànica i Institut de Biomedicina (IBUB), Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
| | - Jaume Granell
- Departament de Química Inorgànica i Orgànica, Secció de Química Inorgànica, Facultat de Quimica, Universitat de Barcelona, Martí i Franquès 1-11. 08028 Barcelona, Spain
| | - Manuel Martinez
- Departament de Química Inorgànica i Orgànica, Secció de Química Inorgànica, Facultat de Quimica, Universitat de Barcelona, Martí i Franquès 1-11. 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
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