Enantioselective Acetalization by Dynamic Kinetic Resolution for the Synthesis of γ‐Alkoxybutenolides by Thiourea/Quaternary Ammonium Salt Catalysts: Application to Strigolactones
| Autor: | Motohiro Yasui, Ayano Yamada, Chihiro Tsukano, Andrea Hamza, Yoshiji Takemoto, Imre Pápai |
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| Jazyk: | japonština |
| Rok vydání: | 2020 |
| Předmět: |
inorganic chemicals
organic chemicals asymmetric synthesis Enantioselective synthesis General Medicine General Chemistry strigolactones Combinatorial chemistry Catalysis Kinetic resolution acetalization chemistry.chemical_compound chemistry Nucleophile Thiourea Organocatalysis Electrophile Organic synthesis organocatalysis alkylation |
| Zdroj: | Angewandte Chemie. 59(32):13479-13483 |
| ISSN: | 1433-7851 |
| Popis: | Although acetalization is a fundamental transformation in organic synthesis, intermolecular asymmetric acetalization remains an unsolved problem. In this study, a thiourea-ammonium hybrid catalyst was shown to promote the O-alkylation of enols with a racemic γ-chlorobutenolide through dynamic kinetic resolution to give chiral acetals with good enantioselectivity. The catalyst simultaneously activates both the nucleophile and electrophile in a multifunctional manner. This method was applied to the asymmetric synthesis of several strigolactones. DFT calculations suggest that hydrogen-bonding interactions between the chlorine atom of the γ-chlorobutenolide and the tosylamide hydrogen atom of the catalyst, as well as other types of noncovalent catalyst-substrate interactions, are crucial for achieving high stereoselectivity. |
| Databáze: | OpenAIRE |
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