Quantum dots enable direct alkylation and arylation of allylic C(sp3)–H bonds with hydrogen evolution by solar energy

Huang, Cheng; Qiao, Jing; Ci, Rui‐Nan; Wang, Xu‐Zhe; Wang, Yang; Wang, Jing-Hao; Chen, Bin; Tung, Chen‐Ho; Wu, Li‐Zhu

doi:10.1016/j.chempr.2021.01.019

Cited by 67 publications

(53 citation statements)

References 67 publications

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“…Selective functionalization of abundant and readily available allylic C–H bond-containing compounds under mild conditions is still lagging behind even though the allylation reaction plays a vital role in the synthesis of valuable chemical building blocks and commercial chemicals. − Commonly, various organic reagents, such as halide, phosphate, and carbonate, are employed as leaving groups to enable transition-metal-catalyzed allylic substitution reactions. , Considering this low atom-/step-economical process induced by installing and eliminating these leaving groups, the exploration of economical and environmentally benign catalytic systems that can directly functionalize allylic C–H bonds without introducing external functional groups and stoichiometric chemical reagents has received ever-increasing research interest. Very recently, Wu et al have demonstrated a facile and general strategy for the dehydrogenative cross-coupling of allylic C–H bonds with α-amino C–H bonds or heteroarenes under ambient conditions by employing Ni-decorated CdSe QDs as photocatalysts (Figure a) . In this catalytic system, upon visible light irradiation, the holes migrated from the photoexcited CdSe QDs first activate allylic C–H bonds to produce allylic radicals, which can couple with either α-amino radicals produced from α-amino C–H bonds via direct radical coupling reaction or heteroarenes via a Minisci reaction for ensuing C–C bond formation.…”

Section: Recent Developments In Concurrent Organic Synthesis and Hydr...mentioning

confidence: 99%

Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts

et al. 2021

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Merging hydrogen (H 2 ) evolution with oxidative organic synthesis in a semiconductor-mediated photoredox reaction is extremely attractive because the clean H 2 fuel and high-value chemicals can be coproduced under mild conditions using light as the sole energy input. Following this dual-functional photocatalytic strategy, a dreamlike reaction pathway for constructing C−C/C−X (X = C, N, O, S) bonds from abundant and readily available X−H bond-containing compounds with concomitant release of H 2 can be readily fulfilled without the need of external chemical reagents, thus offering a green and fascinating organic synthetic strategy. In this review, we begin by presenting a concise overview on the general background of traditional photocatalytic H 2 production and then focus on the fundamental principles of cooperative photoredox coupling of selective organic synthesis and H 2 production by simultaneous utilization of photoexcited electrons and holes over semiconductor-based catalysts to meet the economic and sustainability goal. Thereafter, we put dedicated emphasis on recent key progress of cooperative photoredox coupling of H 2 production and various selective organic transformations, including selective alcohol oxidation, selective methane conversion, amines oxidative coupling, oxidative cross-coupling, cyclic alkanes dehydrogenation, reforming of lignocellulosic biomass, and so on. Finally, the remaining challenges and future perspectives in this flourishing area have been critically discussed. It is anticipated that this review will provide enlightening guidance on the rational design of such dual-functional photoredox reaction system, thereby stimulating the development of economical and environmentally benign solar fuel generation and organic synthesis of value-added fine chemicals.

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Section: Recent Developments In Concurrent Organic Synthesis and Hydr...mentioning

confidence: 99%

Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts

et al. 2021

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“…22 To evaluate the photocatalytic performance of TPPy-PBT-COF, aerobic cross-dehydrogenative coupling (CDC) was chosen as the model reaction. In previously reported studies, the CDC reactions could be photocatalyzed using metal-complexes, 23 organic dyes, 24 quantum dots 25 and COFs 26,27 upon irradiation with artificial light sources. Before being applied in ''window ledge'' chemistry, the COF was introduced into the Mannich reaction activated using a 5 W LED lamp.…”

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A covalent organic framework as a photocatalyst for window ledge cross-dehydrogenative coupling reactions

Dong

Yang

et al. 2022

Chem. Commun.

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“…Benefiting from the quantum confinement effects, rich surface‐binding properties, broad and intense absorption spectra in the visible region, [8] QDs offer new and versatile ways to serve as photocatalysts for chemical transformation [9] . In this contribution, we found that QDs can activate allylic C−H bond [10] to form allylic radical under visible light irradiation, and the hydrogen atom eliminated from the allylic C−H bond can be reduced for hydrogen evolution. Along with the previous works on the thiol activation to produce thiyl radicals on the surface of QDs, [11] we envision that the allylic radical generated from allylic C−H bond might be captured by thiyl radical on the surface of QDs to achieve radical‐radical cross‐coupling for allylic C(sp 3 )−S bond formation.…”

Section: Methodsmentioning

confidence: 93%

Direct Allylic C(sp³)−H and Vinylic C(sp²)−H Thiolation with Hydrogen Evolution by Quantum Dots and Visible Light

Huang

Qiao

et al. 2021

Angewandte Chemie

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Direct allylic C−H thiolation is straightforward for allylic C(sp3)−S bond formation. However, strong interactions between thiol and transition metal catalysts lead to deactivation of the catalytic cycle or oxidation of sulfur atom under oxidative condition. Thus, direct allylic C(sp3)−H thiolation has proved difficult. Represented herein is an exceptional for direct, efficient, atom‐ and step‐economic thiolation of allylic C(sp3)−H and thiol S−H under visible light irradiation. Radical trapping experiments and electron paramagnetic resonance (EPR) spectroscopy identified the allylic radical and thiyl radical generated on the surface of photocatalyst quantum dots (QDs). The C−S bond formation does not require external oxidants and radical initiators, and hydrogen (H2) is produced as byproduct. When vinylic C(sp2)−H was used instead of allylic C(sp3)−H bond, the radical‐radical cross‐coupling of C(sp2)−H and S−H was achieved with liberation of H2. Such a unique transformation opens up a door toward direct C−H and S−H coupling for valuable organosulfur chemistry.

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Quantum dots enable direct alkylation and arylation of allylic C(sp3)–H bonds with hydrogen evolution by solar energy

Cited by 67 publications

References 67 publications

Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts

Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts

A covalent organic framework as a photocatalyst for window ledge cross-dehydrogenative coupling reactions

Direct Allylic C(sp³)−H and Vinylic C(sp²)−H Thiolation with Hydrogen Evolution by Quantum Dots and Visible Light

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Quantum dots enable direct alkylation and arylation of allylic C(sp3)–H bonds with hydrogen evolution by solar energy

Cited by 67 publications

References 67 publications

Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts

Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts

A covalent organic framework as a photocatalyst for window ledge cross-dehydrogenative coupling reactions

Direct Allylic C(sp3)−H and Vinylic C(sp2)−H Thiolation with Hydrogen Evolution by Quantum Dots and Visible Light

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Product

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Direct Allylic C(sp³)−H and Vinylic C(sp²)−H Thiolation with Hydrogen Evolution by Quantum Dots and Visible Light