CN-122010977-A - Polyfluoroalkoxy aryl substituted triazole nitrogen heterocyclic carbene catalyst and application thereof

CN122010977ACN 122010977 ACN122010977 ACN 122010977ACN-122010977-A

Abstract

The invention discloses a triazole nitrogen heterocyclic carbene catalyst containing polyfluoroalkoxy aryl substituted and application thereof. According to the invention, trifluoro ethoxy or hexafluoroisopropoxy is introduced into the N-phenyl site of the triazole skeleton, 11 triazole nitrogen heterocyclic carbene catalysts containing polyfluoroalkoxy aryl substitution are successfully synthesized, and the catalytic performance of the triazole nitrogen heterocyclic carbene catalysts is explored. Compared with other prior triazole NHCs, the triazole nitrogen heterocyclic carbene catalyst containing the polyfluoroalkoxy aryl substitution shows optimal enantioselectivity and reactivity, and can obtain a target product with a yield of 90% and a yield of 98:2 er under the condition of 10 mol% of catalyst consumption. Meanwhile, the polyfluoroalkoxy aryl substituted triazole nitrogen heterocyclic carbene catalyst is also suitable for photocatalytic and electrocatalytic model reactions. Exhibits excellent reactivity and selectivity in a three-component radical cascade of aldehydes, styrenes and Togni I reagents.

Inventors

ZHU TINGSHUN
ZHAO QING
LI WENCHANG
Lin Kejuan

Assignees

中山大学

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (2)

1. The triazole nitrogen heterocyclic carbene catalyst containing polyfluoroalkoxy aryl substitution is named as NHC1-11, and the structural formula is shown as formula I, II or III: 。
2. the use of the polyfluoroalkoxy aryl substituted triazole nitrogen heterocyclic carbene catalyst of claim 1 in a three-component free radical cascade reaction involving aldehyde, styrene and Togni I reagents.

Description

Polyfluoroalkoxy aryl substituted triazole nitrogen heterocyclic carbene catalyst and application thereof Technical Field The invention relates to the technical field of organic chemistry, in particular to a triazole nitrogen heterocyclic carbene catalyst containing polyfluoroalkoxy aryl substitution and application thereof. Background Triazole Nitrogen Heterocyclic Carbenes (NHCs) are a class of organic catalysts widely used in organic synthesis. Among them, the substituents on the N atom determine the reactivity and stereoselectivity to a large extent, and the selection of aromatic substituents with specific electronic and steric properties is often critical and needs to be designed for different reactions. For example, in asymmetric benzoin condensation reactions (org. Lett., 2007, 9, 2713-2716) and Stetter reactions (chem. Lett.,2008, 37, 2-7), electron-deficient aromatic N-substituents, such as pentafluorophenyl, are often required. In contrast, in the lactonization or lactamization reaction, the reactivity of N-mesityltriazole NHC is significantly better than its N-phenyl counterpart. Meanwhile, the N- (2, 6-dimethoxy phenyl) substituted triazole NHC catalyst shows unique activity in cyclopropene hydroacylation reaction. The unique properties of the fluorine element of the polyfluoroalkoxy gene (such as strong electronegativity, small atomic radius, high C-F bond energy, etc.) exhibit characteristics different from those of the conventional alkoxy group. A typical case is represented in Still-Gennari olefination, wherein the Z/E stereoselectivity can be completely reversed after ethoxy in the Horner-Wadsworth-Emmons reagent is replaced by trifluoroethoxy or hexafluoroisopropoxy, so that the Z-olefin is the main product. In addition, polyfluoroalcohols also exhibit unique properties when used as solvents or additives in various types of conversion reactions. The Li Junlong group uses N-pentafluorophenyl substituted chiral triazoles NHC which catalyze free radical trifluoroacetylation, but has an enantioselectivity of only 56:44 er. The Crame group reports a chiral thiazole NHC with a bulky steric hindrance chiral side chain and a 12-membered ring framework, and the target product can be obtained with a yield of 76% and an enantioselectivity of 96:4 er. However, synthesis of the macrocyclic skeleton is difficult, compared to the commercially available 7-membered ring skeleton catalysts which only provide poor enantioselectivity (60:40 er). Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a triazole nitrogen heterocyclic carbene catalyst containing polyfluoroalkoxy aryl substituted, which can obviously improve the enantioselectivity of the catalyst. In order to achieve the above purpose, the present invention adopts the following technical scheme: The triazole nitrogen heterocyclic carbene catalyst containing polyfluoroalkoxy aryl substitution is named as NHC1-11, and the structural formula is shown as formula I, II or III: compared with the prior art, the invention has the following beneficial effects: The invention develops a novel NHC family containing polyfluoroalkoxy aryl substitution. Specifically, the trifluoro ethoxy or hexafluoroisopropoxy is introduced into the N-phenyl site of the triazole skeleton, 11 triazole nitrogen heterocyclic carbene catalysts containing polyfluoroalkoxy aryl substitution are successfully synthesized, and the catalytic performance of the triazole nitrogen heterocyclic carbene catalysts is explored. Compared with other prior triazole NHCs, the triazole nitrogen heterocyclic carbene catalyst containing the polyfluoroalkoxy aryl substitution shows optimal enantioselectivity and reactivity, and can obtain a target product with a yield of 90% and a yield of 98:2 er under the condition of 10 mol% of catalyst consumption. Meanwhile, the invention discovers that the newly synthesized triazole nitrogen heterocyclic carbene catalyst containing the polyfluoroalkoxy aryl substitution is also applicable to photocatalytic and electrocatalytic model reactions. The polyfluoroalkoxy aryl substituted triazole nitrogen heterocyclic carbene catalyst synthesized by the invention shows excellent reactivity and selectivity in the three-component free radical cascade reaction involving aldehyde, styrene and Togni I reagents. Detailed Description Example 1 Synthesis of intermediates TL-S13, TL-S23 The compounds S1 (2, 6-difluoro nitrobenzene) and S2 (1, 3, 5-trifluoro-2-nitrobenzene) are commercial reagents and are directly purchased for use. (1) Synthesis of TL-S11, TL-S21: Sodium hydride (6 g, 150 mmol, 3 eq, 60% dispersion in mineral oil) was added to a 1000 mL round bottom flask dried in a dry box and equipped with a magnetic stirrer. Sodium hydride was washed three times with petroleum ether (50 mL x 3), and the supernatant was removed with a syringe with a long needle tube each time. Anhydrous toluene (500 mL) was added and the mixture was co