- PHOTOCATALYST SYSTEM AND USE THEREOF IN A PHOTOCATALYTIC PROCESS
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Photocatalyst system and use thereof in a photochemical process The invention relates to a photocatalyst system comprising, in the absence of a further photosensitizer other than the compound of formula (III) or a mixture thereof: (i) a nickel(II) salt, (
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Page/Page column 33; 38-40
(2019/06/13)
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- Sp3 C-H Arylation and Alkylation Enabled by the Synergy of Triplet Excited Ketones and Nickel Catalysts
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Triplet ketone sensitizers are of central importance within the realm of photochemical transformations. Although the radical-type character of triplet excited states of diaryl ketones suggests the viability for triggering hydrogen-atom transfer (HAT) and single-electron transfer (SET) processes, among others, their use as multifaceted catalysts in C-C bond-formation via sp3 C-H functionalization of alkane feedstocks still remains rather unexplored. Herein, we unlock a modular photochemical platform for forging C(sp3)-C(sp2) and C(sp3)-C(sp3) linkages from abundant alkane sp3 C-H bonds as functional handles using the synergy between nickel catalysts and simple, cheap and modular diaryl ketones. This method is distinguished by its wide scope that is obtained from cheap catalysts and starting precursors, thus complementing existing inner-sphere C-H functionalization protocols or recent photoredox scenarios based on iridium polypyridyl complexes. Additionally, such a platform provides a new strategy for streamlining the synthesis of complex molecules with high levels of predictable site-selectivity and preparative utility. Mechanistic experiments suggest that sp3 C-H abstraction occurs via HAT from the ketone triplet excited state. We believe this study will contribute to a more systematic utilization of triplet excited ketones as catalysts in metallaphotoredox scenarios.
- Shen, Yangyang,Gu, Yiting,Martin, Ruben
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supporting information
p. 12200 - 12209
(2018/09/27)
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- Raney Ni-Al alloy-mediated reduction of benzils in wate
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Raney Ni-Al alloy in a dilute aqueous alkaline solution has been shown to be a powerful reducing agent and is highly effective for the reduction of alkylbenzils and alkoxybenzils to afford the corresponding 1,2-diarylethers at 90°C, in the absence of organic solvents. 4,4'-Dinitrobenzil was transformed selectively to 1,2-bis(4-aminophenyl) ethane.
- Liu, Guo-Bin,Zhao, Hong-Yun,Dai, Lu,Thiemann, Thies,Tashiro, Hideki,Tashiro, Masashi
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experimental part
p. 579 - 581
(2010/02/28)
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- Palladium-catalyzed negishi cross-coupling reactions of unactivated alkyl iodides, bromides, chlorides, and tosylates
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A single method (2% Pd2(dba)3/8% PCyp 3/NMI in THF/NMP at 80°C; Cyp = cyclopentyl) achieves the cross-coupling of a range of β-hydrogen-containing primary alkyl iodides, bromides, chlorides, and tosylates with an array of alkyl-, alkenyl-, and arylzinc halides. The process is compatible with a variety of functional groups, including esters, amides, imides, nitriles, and heterocycles.
- Zhou, Jianrong,Fu, Gregory C.
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p. 12527 - 12530
(2007/10/03)
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- Sulphenamides as synthetic precursors of aminyl radicals
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Sulphenamides, readily synthesised from reaction between benzenesulphenyl derivatives and amines, undergo facile reaction with radical generating reagents such as tributyltin hydride to yield aminyl radicals.
- Bowman, W.Russell,Clark, David N.,Marmon, Robert J.
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p. 6441 - 6444
(2007/10/02)
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