Grotjahn, Sascha and Graf, Christina and Zelenka, Jan and Pattanaik, Aryaman and Mueller, Lea and Kutta, Roger Jan and Rehbein, Julia and Roithova, Jana and Gschwind, Ruth M. and Nuernberger, Patrick and Koenig, Burkhard (2024) Reactivity of Superbasic Carbanions Generated via Reductive Radical-Polar Crossover in the Context of Photoredox Catalysis. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 63 (18): e202400815. ISSN 1521-3773
Full text not available from this repository. (Request a copy)Abstract
Photocatalytic reactions involving a reductive radical-polar crossover (RRPCO) generate intermediates with carbanionic reactivity. Many of these proposed intermediates resemble highly reactive organometallic compounds. However, conditions of their formation are generally not tolerated by their isolated organometallic versions and often a different reactivity is observed. Our investigations on their nature and reactivity under commonly used photocatalytic conditions demonstrate that these intermediates are indeed best described as free, superbasic carbanions capable of deprotonating common polar solvents usually assumed to be inert such as acetonitrile, dimethylformamide, and dimethylsulfoxide. Their basicity not only towards solvents but also towards electrophiles, such as aldehydes, ketones, and esters, is comparable to the reactivity of isolated carbanions in the gas-phase. Previously unsuccessful transformations thought to result from a lack of reactivity are explained by their high reactivity towards the solvent and weakly acidic protons of reaction partners. An intuitive explanation for the mode of action of photocatalytically generated carbanions is provided, which enables methods to verify reaction mechanisms proposed to involve an RRPCO step and to identify the reasons for the limitations of current methods. Photocatalytic reactions with a reductive radical-polar crossover (RRPCO) involve intermediates with carbanionic reactivity. These are best described as free carbanions. Reactions with such carbanions depend on the balance between their nucleophilicity and basicity. Deprotonation of reaction partners and common organic solvents such as acetonitrile, dimethylformamide, and dimethylsulfoxide is the main competing reaction to nucleophilic addition. image
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | COLLISION-INDUCED DISSOCIATION; MOLECULAR-ORBITAL METHODS; BASIS-SETS; EQUILIBRIUM ACIDITIES; 3RD-ROW ATOMS; POTENTIALS; STYRENES; BENZYLATION; MECHANISM; ALDEHYDES; Photocatalysis; Carbanions; Electron transfer; Basicity; Isotope effects |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie > Lehrstuhl Prof. Dr. Burkhard König Chemistry and Pharmacy > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Physical Chemistry I > Prof. Dr. Patrick Nürnberger |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 16 Dec 2025 08:03 |
| Last Modified: | 16 Dec 2025 08:03 |
| URI: | https://pred.uni-regensburg.de/id/eprint/64019 |
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