Enantioselective Synthesis and Racemization of (-)-Sinoracutine
| Autor: | Nynke A. Vepřek, Andreas B. Bellan, Giulio Volpin, Dirk Trauner |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Cyclopentenone
Pyrrolidines 010405 organic chemistry Chemistry Stereochemistry Absolute configuration Enantioselective synthesis Molecular Conformation Stereoisomerism General Chemistry Cyclopentanes 010402 general chemistry 01 natural sciences Levorotatory Catalysis 0104 chemical sciences Stereocenter chemistry.chemical_compound Alkaloids Enantiomer Enantiomeric excess Racemization |
| Zdroj: | Angewandte Chemie (International ed. in English). 56(3) |
| ISSN: | 1521-3773 |
| Popis: | Sinoracutine is a recently isolated alkaloid with unusual stereochemical and biological properties. It features an unprecedented tetracyclic 6/6/5/5 skeleton that bears an N-methylpyrrolidine ring fused to a cyclopentenone. Interestingly, both enantiomers of sinoracutine have been independently isolated from the same plant, yet the molecule does not appear to occur as a racemate. Here, we present a short synthesis of (−)-sinoracutine that relies on a highly diastereoselective Pauson–Khand reaction and a Mandai–Claisen reaction to install the quaternary stereocenter. Our work establishes the absolute configuration of the levorotatory isomer and suggests that the optical purity of sinoracutine varies in nature due to its gradual racemization. Experimental evidence supports this proposal, and a plausible mechanism for the racemization is provided. |
| Databáze: | OpenAIRE |
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