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Relevant academic research and scientific papers

Asymmetric α-hydroxylation of β-dicarbonyl compounds by C-2′ modified cinchonine-derived phase-transfer catalysts in batch and flow microreactors

The asymmetric α-hydroxylation of β-dicarbonyl compounds was catalyzed by C-2′-modified cinchonine-derived phase-transfer catalysts. Excellent yields (up to 95%) and good enantioselectivities (up to 89% ee) were obtained. The reaction was carried out in a flow microreactor and similar results were obtained (up to 93% yield, 84% ee), the residence time was shortened from 24 h in batch to 2 h.

Enantioselective photooxygenation of β-dicarbonyl compounds in batch and flow photomicroreactors

A series of C-2′ modified cinchonine-derived phase-transfer catalysts were synthesized and used in the enantioselective photo-organocatalytic aerobic oxidation of β-dicarbonyl compounds with excellent yields (up to 97%) and high enantioselectivities (up to 90% ee). Furthermore, the reaction was carried out in a flow photomicroreactor, in which the heterogeneous gas-liquid-liquid asymmetric photocatalytic oxidation reaction was performed affording good yields (up to 97%) and enantioselectivities (up to 86% ee) within 0.89 min.

A kind of new optical catalytic asymmetric oxidation for the preparation of chiral α - hydroxy - β - dicarbonyl compounds (by machine translation)

A kind of new optical catalytic asymmetric oxidation for the preparation of chiral α - hydroxy - β - dicarbonyl compound, which belongs to the technical field of organic synthesis. The method utilizes acetic derivative of the phase-transfer catalyst, in t

Visible-Light-Driven Enantioselective Aerobic Oxidation of β-Dicarbonyl Compounds Catalyzed by Cinchona-Derived Phase Transfer Catalysts in Batch and Semi-Flow

The direct asymmetric α-hydroxylation of β-dicarbonyl compounds has been developed using cinchona-derived phase-transfer catalysts in batch and semi-flow processes. Using visible light as the driving force and air as oxidant, the corresponding products were obtained in excellent yields (up to 96%) and good enantioselectivities (up to 90% ee). The catalyst acts as a chiral center and a catalytic center and forms a chiral enolate complex with the substrate to act as a photosensitive center in the reaction. The use of semi-flow photochemical processes allowed a reduction in reaction time (24 h to 0.89 h) and good yields (up to 93%) and enantioselectivities (up to 88% ee) were obtained.

Novel method for realizing visible light catalytic asymmetric oxidation by using micro reactor

The invention belongs to the field of flow chemistry, and provides a novel method for realizing visible light catalytic asymmetric oxidation by using a micro reactor. According to the method, a chiralbeta-hydroxy-beta-dicarbonyl compound is prepared conti

Bifunctional metal-free photo-organocatalysts for enantioselective aerobic oxidation of β-dicarbonyl compounds

A series of bifunctional metal-free photo-organocatalysts have been developed by grafting the photosensitizer to cinchona-derived phase-transfer catalysts. Using air as a green oxidant and visible light as the driving force, these catalysts are applied to the oxidation of a range of β-dicarbonyl compounds in good yields (up to 97%) and enantioselectivities (up to 93:7 er).

Novel method for asymmetric alpha-hydroxylation of photo-oxygenation beta-dicarbonyl compound based on C-2' phase transfer catalyst

The invention belongs to the technical fields of organic synthesis and provides a novel method for asymmetric alpha-hydroxylation of a photo-oxygenation beta-dicarbonyl compound based on a C-2' phase transfer catalyst.The beta-dicarbonyl compound, the cinchona alkaloid C-2' phase transfer catalyst and an organic photosensitizer are stirred in a solvent, alkali is added, strong stirring reaction is performed in the air under the condition of visible light, the reaction temperature is 50-70 DEG C, the reaction time is 1-4 hours, and a chiral alpha-hydroxyl-beta-dicarbonyl compound with the yield no lower than 70% and the enantiomeric excess selectivity no lower than 60% ee is obtained; derivatization is conducted on a cheap cinchona alkaloid C-2' potential easy to obtain a series of chiral phase transfer catalysts having higher catalytic activity, molecules are successively oxidized into an oxidant, and the asymmetric alpha-hydroxylation of the photo-oxygenation beta-dicarbonyl compound is achieved.The method has good substrate applicability and environmental friendliness.

Novel method for asymmetric alpha-hydroxylation of beta-dicarbonyl compound by photo-oxidation under action of quinine derived N-O phase transfer catalyst

The invention belongs to the technical field of organic synthesis and provides a novel method for asymmetric alpha-hydroxylation of a beta-dicarbonyl compound by photo-oxidation under action of a quinine derived N-O phase transfer catalyst.The method incl

Diterpenoid alkaloid lappaconine derivative catalyzed asymmetric α-hydroxylation of β-dicarbonyl compounds with hydrogen peroxide

A new framework derived from the commercially available diterpenoid alkaloid lappaconitine was evaluated as a Bronsted base catalyst for the enantioselective α-hydroxylation of β-dicarbonyl compounds by using 30% hydrogen peroxide as a green and highly practical source of oxygen. This protocol allows convenient access to the corresponding α-hydroxy-β- oxo esters, α-hydroxy-β-oxo amides and (-)-kjellmanianone with up to 98% yield and 92% ee. Copyright