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A class of chiral carbene precursor compounds with sandwich structure and synthesis method thereof

A precursor compound and sandwich structure technology, which is applied to a class of chiral carbene precursor compounds with a sandwich structure and the field of synthesis thereof, and can solve the problem of decreased carbene stability, difficulty in obtaining metal-carbene complexes, and limiting sandwich structure carbene Ligand application and other issues, to achieve the effect of asymmetric hydrosilylation, novel structure and fewer reaction steps

Active Publication Date: 2021-02-12
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The nitrogen-heterocyclic carbene with a sandwich structure can effectively trap the coordination core region and provide an ideal steric hindrance environment in the metal complexes in which the carbene participates in the formation. Currently, there are few chiral carbene ligands with a sandwich structure, and The introduction of the sandwich plane leads to a decrease in the stability of the carbene, making it difficult to obtain metal-carbene complexes, which limits the application of the sandwich-structured carbene ligands in catalytic reactions (references: Albright, A.; Eddings, D.; Black, R.; Welch, C.J.; Gerasimchuk, N.N.; Gawley, R.E.J. Org. Chem. 2011, 76, 7341-7351.)
Therefore, it is imminent to develop a new chiral carbene ligand with a sandwich structure. However, there are still many challenges in this type of structure: 1) the introduction of the aryl plane of the sandwich structure; 2) the long-distance transmission of chiral fragments; The terminal aryl plane is located on the upper and lower sides, which inhibits the arrangement of the steric hindrance group to the two sides of the carbene mother ring; 4) the structural stability of the carbene and the difficulty of combining with the metal precursor

Method used

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  • A class of chiral carbene precursor compounds with sandwich structure and synthesis method thereof
  • A class of chiral carbene precursor compounds with sandwich structure and synthesis method thereof
  • A class of chiral carbene precursor compounds with sandwich structure and synthesis method thereof

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Experimental program
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Effect test

Embodiment 1

[0050] The synthesis of embodiment 1 compound (R)-2

[0051]

[0052]Under nitrogen atmosphere, (R)-tetrahydronaphthylamine (R)-1 (7.36 g, 50 mmol) was dissolved in 80 mL tetrahydrofuran in a 250 mL reaction flask. At -78°C, n-butyl lithium (34.3 mL, c=1.6 mol / L, 55 mmol) was added dropwise to the reaction solution, and stirred for 30 minutes. At this temperature, a tetrahydrofuran solution (40 mL) of tert-butyldimethylsilyl chloride (8.29 g, 55 mmol) was added dropwise, and stirred overnight after naturally returning to room temperature. After stopping the reaction, the solvent was removed under reduced pressure and used directly in subsequent reactions. Under nitrogen atmosphere, the above crude product was dissolved in 150 mL of ether in a 500 mL reaction flask. At -78°C, n-butyllithium (93.8 mL, c=1.6 mol / L, 150 mmol) was added dropwise to the reaction solution, and the reaction solution returned to room temperature within 3 hours, and continued to stir for 1 hour. T...

Embodiment 2

[0053] The synthesis of embodiment 2 compound (R)-3

[0054]

[0055] In a 250 mL reaction flask, the iodo substrate (R)-2 (5.46 g, 20 mmol) and triethylamine (3.04 g, 30 mmol) were dissolved in 50 mL of dichloromethane. At 0°C, a dichloromethane solution (50 mL) of di-tert-butyl dicarbonate (5.24 g, 24 mmol) was added dropwise into the reaction system, and stirred overnight at room temperature. After stopping the reaction, 50 mL of water was added to the reaction liquid, extracted with dichloromethane, the organic phases were combined, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure and separated by column chromatography to obtain 6.94 g of a yellow viscous liquid with a yield of 93%. 1 H NMR (400MHz, CDCl 3 )δ7.72(d, J=7.7Hz, 1H), 7.07(d, J=7.6Hz, 1H), 6.87(t, J=7.7Hz, 1H), 4.73-4.17(m, 2H), 2.80- 2.65(m,2H),2.22(d,J=11.9Hz,1H),1.78-1.62(m,3H),1.46(s,9H). 13 C NMR (100MHz, CDCl 3 )δ154.8, 140.5, 138.0, 129.6, 129.2, 103.2, 79.3...

Embodiment 3

[0056] The synthesis of embodiment 3 compound (R)-4

[0057]

[0058] Under nitrogen atmosphere, in 250mL Schlenk bottle, add substrate (R)-3 (6.72g, 18mmol), 4-methoxyphenylboronic acid (4.10g, 27mmol), tetrakis (triphenylphosphine) palladium (1.04g, 0.9mmol), 2mol / L potassium carbonate (4.98g, 36mmol) aqueous solution (18mL) and ethylene glycol dimethyl ether (180mL), the reaction solution was heated to 85°C and refluxed for 36 hours. The reaction system was cooled to room temperature, then poured into 50 mL of water, extracted with ethyl acetate, combined the organic phases, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure and separated by column chromatography to obtain the crude coupling target product, which could be directly used in subsequent reactions without further purification.

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Abstract

The present invention provides a class of chiral carbene precursor compounds with a sandwich structure. Optically pure 1-aminotetrahydronaphthalene is used as a starting material, and a palladium-catalyzed coupling reaction is carried out to realize cross-coupling with arylboronic acid, and then with 1-aminotetrahydronaphthalene as a starting material. , the double alkylation reaction of 2-dibromoethane or the coupling reaction with 1,2-dibromobenzene under palladium catalysis, and finally carry out ring-closing reaction with ethyl orthoformate to obtain a kind of hand with a sandwich structure. Sex carbene precursor compounds. The invention can effectively synthesize optically pure sandwich structure chiral carbene precursor compound, has simple operation and high yield, and the chiral carbene can effectively realize the asymmetric hydrosilation reaction of C=O.

Description

technical field [0001] The invention relates to a class of chiral carbene precursor compounds with a sandwich structure and a synthesis method thereof. Background technique [0002] Nitrocyclic carbene is a class of potential small molecule catalysts and ligands. Thanks to the strong σ donor, adjustable π acceptor properties and large steric hindrance, the carbene complex exhibits very high thermal and chemical stability, and has become an important carrier for many catalytic reactions (reference: a) Marion, N.; Díez-González, S.; Nolan, S.P. Angew. Chem. Int. Ed. 2007, 46, 2988-3000; b) Díez-González, S.; Marion, N.; Nolan, S.P.Chem. Rev. 2009, 109, 3612-3676.). The development and application of chiral monodentate ligands is a very challenging research direction. Azacyclic carbene can form a strong metal-carbon bond with the central metal, which effectively overcomes the monodentate ligand structure caused by a single coordination site. Congenital disadvantages. More a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D233/06C07D235/06C07F1/08B01J31/22B01J31/12C07C29/143C07C33/24
CPCB01J31/12B01J31/2273B01J2231/643C07B2200/07C07B2200/13C07C29/143C07D233/06C07D235/06C07F1/08C07C33/24
Inventor 周永贵刘聪沈宏强孙蕾
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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