Catalytic asymmetric C–C cross-couplings enabled by photoexcitation
| Autor: | Adriana Faraone, Paolo Melchiorre, Daniele Mazzarella, Giacomo E. M. Crisenza, Eugenio Gandolfo |
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| Přispěvatelé: | Crisenza G.E.M., Faraone A., Gandolfo E., Mazzarella D., Melchiorre P. |
| Rok vydání: | 2021 |
| Předmět: |
metal catalysis
photochemistry radical electrin transfer Allylic rearrangement 010405 organic chemistry Chemistry organic chemicals General Chemical Engineering Radical Enantioselective synthesis food and beverages General Chemistry 010402 general chemistry 01 natural sciences Combinatorial chemistry Reductive elimination 0104 chemical sciences Stereocenter Catalysis Stereoselectivity Reactivity (chemistry) |
| Zdroj: | Nature Chemistry |
| ISSN: | 1755-4349 1755-4330 |
| Popis: | Enantioselective catalytic processes are promoted by chiral catalysts that can execute a specific mode of catalytic reactivity, channeling the chemical reaction through a certain mechanistic pathway. Here, we show how by simply using visible light we can divert the established ionic reactivity of a chiral allyl–iridium(iii) complex to switch on completely new catalytic functions, enabling mechanistically unrelated radical-based enantioselective pathways. Photoexcitation provides the chiral organometallic intermediate with the ability to activate substrates via an electron-transfer manifold. This redox event unlocks an otherwise inaccessible cross-coupling mechanism, since the resulting iridium(ii) centre can intercept the generated radicals and undergo a reductive elimination to forge a stereogenic centre with high stereoselectivity. This photochemical strategy enables difficult-to-realize enantioselective alkyl–alkyl cross-coupling reactions between allylic alcohols and readily available radical precursors, which are not achievable under thermal activation. [Figure not available: see fulltext.] |
| Databáze: | OpenAIRE |
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