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

Tang, Xiaofei; Zhao, Jianzhang; Wu, Yufeng; Feng, Shihao; Yang, Fan; Yu, Zongyi; Meng, Qingwei

doi:10.1002/adsc.201900777

Cited by 29 publications

(11 citation statements)

References 75 publications

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“…Almost simultaneously, similar results were obtained in another report on the enantioselective photooxidation of carbonyl compounds. In this case, reactions were performed without TPP and under blue LED irradiation . The authors claim that the blue LEDs directly excite the triplet oxygen, without the need of a photosensitizer.…”

Section: Flow Photochemistrymentioning

confidence: 99%

Technological Innovations in Photochemistry for Organic Synthesis: Flow Chemistry, High-Throughput Experimentation, Scale-up, and Photoelectrochemistry

et al. 2021

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Photoinduced chemical transformations have received in recent years a tremendous amount of attention, providing a plethora of opportunities to synthetic organic chemists. However, performing a photochemical transformation can be quite a challenge because of various issues related to the delivery of photons. These challenges have barred the widespread adoption of photochemical steps in the chemical industry. However, in the past decade, several technological innovations have led to more reproducible, selective, and scalable photoinduced reactions. Herein, we provide a comprehensive overview of these exciting technological advances, including flow chemistry, high-throughput experimentation, reactor design and scale-up, and the combination of photo- and electro-chemistry.

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Section: Flow Photochemistrymentioning

confidence: 99%

Technological Innovations in Photochemistry for Organic Synthesis: Flow Chemistry, High-Throughput Experimentation, Scale-up, and Photoelectrochemistry

et al. 2021

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“…188 In 2019, the same group discovered that the reaction also proceeds with a similar catalyst 142 lacking the photosensitizing unit. 189 As in the Melchiorre precedent above, an EDA complex between the deprotonated substrate enolate and the catalyst was proposed. The authors proposed that the excited EDA complex sensitizes oxygen, which then reacts with the enolate, eventually affording the hydroxylated product.…”

Section: Enamine and Iminiummentioning

confidence: 87%

Chiral Photocatalyst Structures in Asymmetric Photochemical Synthesis

et al. 2021

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Asymmetric catalysis is a major theme of research in contemporary synthetic organic chemistry. The discovery of general strategies for highly enantioselective photochemical reactions, however, has been a relatively recent development, and the variety of photoreactions that can be conducted in a stereocontrolled manner is consequently somewhat limited. Asymmetric photocatalysis is complicated by the short lifetimes and high reactivities characteristic of photogenerated reactive intermediates; the design of catalyst architectures that can provide effective enantiodifferentiating environments for these intermediates while minimizing the participation of uncontrolled racemic background processes has proven to be a key challenge for progress in this field. This review provides a summary of the chiral catalyst structures that have been studied for solution-phase asymmetric photochemistry, including chiral organic sensitizers, inorganic chromophores, and soluble macromolecules. While some of these photocatalysts are derived from privileged catalyst structures that are effective for both ground-state and photochemical transformations, others are structural designs unique to photocatalysis and offer insight into the logic required for highly effective stereocontrolled photocatalysis.

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“…Meng and co-workers reported a visible-light driven heterogeneous gas–liquid–liquid asymmetric aerobic oxidation of β-dicarbonyl compounds catalyzed by a cinchona-derived phase-transfer catalyst in a flow photomicroreactor. 239 The catalyst acts as a chiral center and a catalytic center and forms a chiral enolate complex with the substrate acting as a photosensitive center in the reaction (Fig. 76).…”

Section: Oxidation Reactions In Flow Photochemistrymentioning

confidence: 99%