Enantioselective β-Protonation of Enals via a Shuttling Strategy
| Autor: | Leming Wang, Jiean Chen, Yong Huang, Pengfei Yuan |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Chemistry Stereochemistry organic chemicals Enantioselective synthesis Protonation General Chemistry 010402 general chemistry 01 natural sciences Biochemistry Combinatorial chemistry Catalysis 0104 chemical sciences chemistry.chemical_compound Colloid and Surface Chemistry Yield (chemistry) Electrophile Stereoselectivity Brønsted–Lowry acid–base theory Carbene |
| Zdroj: | Journal of the American Chemical Society. 139:7045-7051 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.7b02889 |
| Popis: | Remote asymmetric protonation is a longstanding challenge due to the small size of protons. Reactions involving electron-deficient olefins pose a further difficulty due to the electrophilic nature of these substrates. We report a shuttling system that delivers a proton in a highly enantioselective manner to the β-carbon of enals using a chiral N-heterocyclic carbene (NHC) catalyst. Choices of a Brønsted base shuttle and a Brønsted acid cocatalyst are critical for highly stereoselective β-protonation of the homoenolate intermediate and regeneration of the NHC catalyst results in functionalization of the carbonyl group. Thioesters with a β-chiral center were prepared in a redox-neutral transformation with an excellent yield and ee. |
| Databáze: | OpenAIRE |
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