The first enantioselective direct α-hydroxylation of β-oxo esters was developed by using phase-transfercatalysis. 1-Indanone-derived 1-adamantyl (1-Ad) β-oxo esters, in the presence of commercially available cumyl hydroperoxide and a cinchonine-based ammonium salt, resulted in the corresponding products with 69–91 % yield and 65–74 % ee. The reaction had also been successfully scaled-up to a gram
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).
An efficient and enantioselective photo-organocatalytic [small alpha]-hydroxylation of [small beta]- dicarbonyl compounds using molecular oxygen has been extended. This simple catalytic procedure is applicable to a range of [small beta]-keto esters and [small beta]-keto...
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 chiral photocatalysts in batch and semi‐flow processes. Using visiblelight 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
A series of C-2' modified cinchonine-derived phase-transfer catalysts were synthesized and used in the enantioselective photo-organocatalytic aerobic oxidation of β-dicarbonylcompounds 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