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Visible‐Light‐Driven Enantioselective Aerobic Oxidation of β‐Dicarbonyl Compounds Catalyzed by Cinchona‐Derived Phase Transfer Catalysts in Batch and Semi‐Flow
Author(s) -
Tang XiaoFei,
Zhao JingNan,
Wu YuFeng,
Feng ShiHao,
Yang Fan,
Yu ZongYi,
Meng QingWei
Publication year - 2019
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201900777
Subject(s) - chemistry , catalysis , enantioselective synthesis , hydroxylation , cinchona , substrate (aquarium) , cinchona alkaloids , photochemistry , transfer agent , phase (matter) , flow chemistry , photoredox catalysis , combinatorial chemistry , organic chemistry , photocatalysis , polymer , oceanography , monomer , geology , enzyme
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.