Chiral pyridine-derived N, B ligand, preparation method and application in iridium-catalyzed asymmetric boronation reaction

A chiral and pyridine technology, which is applied in the application field of iridium-catalyzed asymmetric borylation reaction, can solve the problems of contradiction between activity and selectivity, poor structure modifiability, difficult modular synthesis, etc., and achieve excellent enantioselectivity, The cost of raw materials is low, and the effect of synthesis is easy to obtain

Active Publication Date: 2021-04-30
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Difficulty in introducing chiral elements into the planar structure, contradiction between activity and selectivity due to steric hindrance, poor structure modification, and difficulty in modular synthesis are the main challenges in the design of chiral pyridines.

Method used

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  • Chiral pyridine-derived N, B ligand, preparation method and application in iridium-catalyzed asymmetric boronation reaction
  • Chiral pyridine-derived N, B ligand, preparation method and application in iridium-catalyzed asymmetric boronation reaction
  • Chiral pyridine-derived N, B ligand, preparation method and application in iridium-catalyzed asymmetric boronation reaction

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0081] Synthesis of chiral pyridine-derived N,B ligands:

[0082] 1.1)

[0083]

[0084]In a 250mL single-necked bottle, add bromocyclopentenone (17.71g, 110mmol), diethyl malonate (25.05mL, 165mmol), tetrahexylammonium bromide (4.78g, 11mmol), potassium carbonate (91.21g , 660mmol), and 60mL of 1,2-dichloroethane, heated to reflux at 90°C for 8 hours. Aftertreatment: filter the reaction solution with a Buchner funnel, rinse the filter cake with dichloromethane, collect the filtrate, concentrate, separate and purify by column chromatography to obtain the racemic ketone (colorless oily liquid, 86% yield) shown in formula (2) .

[0085] 1.2)

[0086]

[0087] The racemic ketone represented by formula (2) (9.6g, 40mmol), (R)-tert-butylsulfinamide (5.33g, 44mmol), tetraethyl titanate (18.25g, 80mmol), 40mL without Mix water and 1,2-dichloroethane, and heat to reflux at 90°C for 12 hours. Post-reaction treatment: Quench the reaction with saturated ammonium chloride solut...

Embodiment 2

[0111] 1.1) In a 10mL single-necked bottle, add bromocyclopentenone (1mmol), diethyl malonate (1.0mmol), tetrahexylammonium bromide (0.15mmol), potassium carbonate (4mmol), and 2mL of 1, 2-dichloroethane, heated to reflux at 84°C for 10 hours. Aftertreatment: filter the reaction solution with a Buchner funnel, rinse the filter cake with dichloromethane, collect the filtrate, concentrate, separate and purify by column chromatography to obtain the racemic ketone (colorless oily liquid, 86% yield) shown in formula (2) .

[0112] 1.2) Mix the racemic ketone (1mmol) represented by formula (2), (R)-tert-butylsulfinamide (1.2mmol), tetraethyl titanate (3mmol), 2mL of anhydrous 1,2-bis Mix ethyl chloride and heat to reflux at 80°C for 18 hours. Post-reaction treatment: Quench the reaction with saturated ammonium chloride solution at 0°C, filter with suction, collect the filtrate, extract the aqueous phase with dichloromethane three times, combine the organic phase, back-extract with...

Embodiment 3

[0121] 1.1) In a 10mL single-necked bottle, add bromocyclopentenone (1mmol), diethyl malonate (1.5mmol), tetrahexylammonium bromide (0.2mmol), potassium carbonate (5mmol), and 2mL of 1, 2-dichloroethane, heated to reflux at 80°C for 12 hours. Aftertreatment: filter the reaction solution with a Buchner funnel, rinse the filter cake with dichloromethane, collect the filtrate, concentrate, separate and purify by column chromatography to obtain the racemic ketone (colorless oily liquid, 86% yield) shown in formula (2) .

[0122] 1.2) Mix the racemic ketone (1mmol) represented by formula (2), (R)-tert-butylsulfinamide (1.5mmol), tetraethyl titanate (2.5mmol), 2mL of anhydrous 1,2- Dichloroethane was mixed and heated to reflux at 85°C for 15 hours. Post-reaction treatment: Quench the reaction with saturated ammonium chloride solution at 0°C, filter with suction, collect the filtrate, extract the aqueous phase with dichloromethane three times, combine the organic phase, back-extrac...

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Abstract

The invention relates to a chiral pyridine-derived N, B ligand and a preparation method thereof, and an application of the chiral pyridine-derived N, B ligand in iridium-catalyzed asymmetric boronation reaction, the chiral pyridine derivative and PhMe2Si-B (NiPr2) 2 are subjected to a reaction in toluene at 125-135 DEG C to obtain the chiral pyridine-derived N, B ligand; and the ligand is used in iridium catalyzed asymmetric boronation reaction, since the ligand is an N, B bidentate ligand, the catalytic activity of central metal iridium can be significantly improved, the chiral pyridine part is a rigid fused ring structure skeleton, and the whole ligand has a relatively rigid and stable chiral space, forms a stable complex after coordination with metal iridium, and has a good application prospect in iridium catalyzed asymmetric boronation reaction. In the reaction process, the chiral environment does not change, and introduction of a five-membered ring and a three-membered ring does not significantly increase steric hindrance of pyridine ortho-position, so that catalytic activity of metal iridium is not affected. The ligand provided by the invention shows excellent reaction activity and enantioselectivity in iridium catalyzed asymmetric boronation reaction.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and relates to chiral pyridine-derived N and B ligands, a preparation method and an application in iridium-catalyzed asymmetric borylation reactions. Background technique [0002] Chiral ligands are the key part of regulating catalyst activity and reaction stereoselectivity in asymmetric metal catalysis to realize the synthesis of single enantiomers of products. Pyridine is the most widely used ligand structural unit in catalysis, but so far there is a lack of universal chiral pyridine skeletons, which restricts the development of many asymmetric catalytic reactions. For example, A chiral bipyridine ligand PINDY was synthesized from natural monoterpene pinene and applied to reactions such as cyclopropanation and allyl oxidation (PINDY: ANovel, Pinene-Derived Bipyridine Ligand and Its Application in Asymmetric Copper(I) -Catalyzed Allylic Oxidation, Malkov, A.V.; Bella, M.; Langer, V.; ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F7/08C07F5/02C07D491/113C07D221/16C07D213/30C07B53/00B01J31/22
CPCC07F7/0812C07F7/083C07B53/00C07D221/16C07D491/113C07F5/025C07D213/30B01J31/184C07B2200/07B01J2531/827
Inventor 李鹏飞宋沛东
Owner XI AN JIAOTONG UNIV
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