Regio- and Stereoselective Biocatalytic Monoamination of a Triketone Enables Asymmetric Synthesis of Both Enantiomers of the Pyrrolizidine Alkaloid Xenovenine Employing Transaminases
| Autor: | Joerg H. Schrittwieser, Stefan E. Payer, Robert C. Simon, Wolfgang Kroutil, Barbara Grischek |
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| Rok vydání: | 2015 |
| Předmět: |
chemistry.chemical_classification
Ketone Pyrrolizidine alkaloid Bicyclic molecule 010405 organic chemistry Stereochemistry Chemistry Enantioselective synthesis Total synthesis General Chemistry 010402 general chemistry 01 natural sciences 0104 chemical sciences Biocatalysis Organic chemistry Stereoselectivity Amination |
| Zdroj: | Advanced Synthesis & Catalysis. 358:444-451 |
| ISSN: | 1615-4150 |
| DOI: | 10.1002/adsc.201500781 |
| Popis: | The (+)- as well as the (−)-enantiomer of the pyrrolizidine alkaloid xenovenine were prepared within five steps with 17 and 30% overall yields, respectively, in optically pure form, >99% ee as well as >99% de. In the asymmetric key step a transaminase performed a regio- and stereoselective monoamination of a triketone. By employing two enantiocomplementary transaminases from Arthrobacter sp. both enantiomers were accessible. The triketone was readily prepared via two steps starting from commercially available, achiral 2-(n-heptyl)furan. In the final catalytic hydrogenation step, the newly introduced chiral centre directed hydrogen addition to form preferentially the desired (5Z,8E)-diastereomer. The regio- and stereoselective amination of a single ketone moiety out of three allowed the performance of the shortest and highest yielding total synthesis of the bicyclic showcase pyrrolizidine alkaloid without the need for protecting strategies. |
| Databáze: | OpenAIRE |
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