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Chiral pyrroline synthetic method by palladium-catalyzed asymmetric hydrogenation

A dihydropyrrole, asymmetric technology, applied in the direction of organic chemistry, can solve the problems of no literature reports, etc., and achieve the effect of convenient separation, good reactivity and chemical selectivity, and high enantioselectivity

Inactive Publication Date: 2012-12-26
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The synthesis of such compounds by direct catalytic asymmetric hydrogenation of simple pyrroles has not been reported in the literature so far

Method used

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  • Chiral pyrroline synthetic method by palladium-catalyzed asymmetric hydrogenation
  • Chiral pyrroline synthetic method by palladium-catalyzed asymmetric hydrogenation
  • Chiral pyrroline synthetic method by palladium-catalyzed asymmetric hydrogenation

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1: optimization of conditions

[0028] Put palladium precursor: palladium trifluoroacetate (0.005 mmol) and chiral ligand: bisphosphine ligand (0.006 mmol) in the reaction flask, add 1 ml of acetone after nitrogen replacement, stir at room temperature for 1 hour and then concentrate in vacuo to remove Acetone gets the catalyst. Add 1 ml of solvent (toluene and trifluoroethanol (2 / 1) ), stirred for 5 minutes, then dissolved and transferred the previously prepared catalyst into a reaction flask with 2 milliliters of solvent, then put it into a high-pressure reactor, fed hydrogen (45 atmospheric pressure), and reacted at 60° C. for 24 hours. Slowly release the hydrogen gas, stir with 5 ml of saturated sodium bicarbonate at room temperature for 10 minutes to make it alkaline, remove the activator acid, extract with dichloromethane (3×5 ml), combine the organic phases, dry over anhydrous sodium sulfate, filter and spin The solvent is removed by evaporation, and ...

Embodiment 2

[0034] Example 2: Synthesis of various chiral dihydropyrroles by palladium-catalyzed asymmetric hydrogenation 2

[0035]Put palladium trifluoroacetate (0.005 mmol) and (R)-C4-TunePhos (0.006 mmol) into the reaction flask, add 1 ml of acetone after nitrogen replacement, stir at room temperature for 1 hour and then concentrate in vacuo to remove acetone to obtain a catalyst. In the glove box, add 1 ml of solvent (toluene and trifluoroethanol (2 / 1)) to the reaction flask with substrate (0.25 mmol) and ethanesulfonic acid (0.375 mmol) in advance, stir for 5 minutes, and then The previously prepared catalyst was dissolved with 2 ml of solvent and transferred to a reaction bottle, then put into a high-pressure reactor, and hydrogen gas (45 atmospheres) was introduced, and the reaction was carried out at 60° C. for 24 hours. Slowly release the hydrogen gas, stir with 5 ml of saturated sodium bicarbonate at room temperature for 10 minutes to make it alkaline, remove the activator acid...

Embodiment 3

[0048] The difference from Example 2 is that the raw material used is 2,5-dibenzylpyrrole (pyrrole substrate with both 2,5-positions being alkyl).

[0049] The invention has simple and practical operation, easy to obtain raw materials, good enantioselectivity and high yield, and the subsequent conversion of reaction products can be conveniently carried out.

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Abstract

A chiral pyrroline synthetic method by palladium-catalyzed asymmetric hydrogenation is characterized by using a Bronsted acid as an activator, and a catalyst system of a chiral diphosphine complex of palladium. The reaction can be carried out under the following conditions: a reaction temperature at 20-70 DEG C; a reaction solvent of a mixed solvent containing toluene and 2, 2, 2-trifluoroethanol (a volume of PhMe to TFE is 2:1); hydrogen pressure at 13-45 atmospheric pressure; a ratio of a substrate to the catalyst being 50 / 1; a metal precursor of Pd (OCOCF3)2; a chiral ligand of a chiral diphosphine ligand; and the activator of ethyl sulfonic acid (EtSO3H). Unprotected simple 2, 5 bisubstituted pyrrole is subjected to hydrogenation to obtain a corresponding chiral pyrroline product (1-pyrroline), and the enantiomer of the chiral pyrroline product can reach an excessive amount of 92%. The invention has advantages of simple operation, practicality, easily available raw materials, good enantioselectivity and high yield; besides, the reaction product is convenient for subsequent conversion.

Description

technical field [0001] The invention relates to a method for synthesizing chiral dihydropyrrole by using a palladium homogeneous system to catalyze and hydrogenate simple pyrrole with high enantioselectivity. Background technique [0002] Many compounds containing dihydropyrrole structures usually have certain biological activities, and they are widely used in pharmaceuticals, pesticides, agricultural chemicals and devices [(a) Sampedro, D.; Migani, A.; Pepi, A. .; Busi, E.; Basosi, R.; Latterini, L.; Elisei, F.; Fusi, S.; Ponticelli, F.; 9349.(b) Obata, M.; Hirohara, S.; Tanaka, R.; Kinoshita, I.; Ohkubo, K.; Fukuzumi, S.; , 2747.(c) Jones, T.H.; Zottig, V.E.; Robertson, H.G.; .; Fisher, B.L.Proc.Natl.Acad.Sci.U.S.A.2005, 102, 11617. (e) Adams, A.; Kimpe, N.D.Chem.Rev.2006, 106, 2299. (f) Huang, T.-C .; Teng, C.-S.; Chang, J.-L.; Chuang, H.-S.; .]. [0003] Due to the importance of chiral dihydropyrrole compounds in the fields of medicine and synthetic chemistry, some ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D207/20
Inventor 周永贵王躲生
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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