How Radical Are “Radical” Photocatalysts? A Closed-Shell Meisenheimer Complex Is Identified as a Super-Reducing Photoreagent

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(35), P. 14352 - 14359

Published: Aug. 25, 2021

Super-reducing excited states have the potential to activate strong bonds, leading unprecedented photoreactivity. Excited of radical anions, accessed via reduction a precatalyst followed by light absorption, been proposed drive photoredox transformations under super-reducing conditions. Here, we investigate anion naphthalene monoimide as photoreductant and find that doublet state has lifetime 24 ps, which is too short facilitate activity. To account for apparent photoreactivity anion, identify an emissive two-electron reduced Meisenheimer complex monoimide, [NMI(H)]−. The singlet [NMI(H)]− potent reductant (−3.08 V vs Fc/Fc+), long-lived (20 ns), its emission can be dynamically quenched chloroarenes photochemistry, establishing it this competent reported C–C C–P coupling reactivity. These results provide mechanistic basis at highly reducing potentials manifolds lays out clear path development exceptionally photoreagents derived from electron-rich closed-shell anions.

Language: Английский

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Unveiling Potent Photooxidation Behavior of Catalytic Photoreductants

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(11), P. 4125 - 4132

Published: March 16, 2021

We describe a photocatalytic system that reveals latent photooxidant behavior from one of the most reducing conventional photoredox catalysts, N-phenylphenothiazine (PTH). This aerobic photochemical reaction engages difficult to oxidize feedstocks, such as benzene, in C(sp2)–N coupling reactions through direct oxidation. Mechanistic studies are consistent with activation PTH via photooxidation and Lewis acid cocatalysts scavenging inhibitors inextricably formed this process.

Language: Английский

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Recent advancements in the development of molecular organic photocatalysts

Organic & Biomolecular Chemistry, Journal Year: 2021, Volume and Issue: 19(22), P. 4816 - 4834

Published: Jan. 1, 2021

A review on the recent advances of six classes organic photocatalysts with respect to photophysical and redox properties.

Language: Английский

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Brønsted Acid Catalyzed Dearomatization by Intramolecular Hydroalkoxylation/Claisen Rearrangement: Diastereo‐ and Enantioselective Synthesis of Spirolactams

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(52), P. 27164 - 27170

Published: Oct. 21, 2021

Described herein is a novel Brønsted acid catalyzed intramolecular hydroalkoxylation/Claisen rearrangement, allowing the practical and atom-economic synthesis of range valuable spirolactams from readily available ynamides in generally good to excellent yields with diastereoselectivities broad substrate scope. Importantly, an unexpected dearomatization nonactivated arenes heteroaromatic compounds involved this tandem sequence. Moreover, asymmetric version cyclization was also achieved by efficient kinetic resolution chiral phosphoric catalysis. In addition, [3,3]-rearrangement shown be kinetically preferred over related [1,3]-rearrangement theoretical calculations.

Language: Английский

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Energy- and atom-efficient chemical synthesis with endergonic photocatalysis

Nature Reviews Chemistry, Journal Year: 2022, Volume and Issue: 6(10), P. 745 - 755

Published: Sept. 23, 2022

Language: Английский

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