Organocatalytic Stereoselective Synthesis of Acyclic γ-Nitrothioesters with All-Carbon Quaternary Stereogenic Centers
| Autor: | Yukihiro Arakawa, Sven P. Fritz, Helma Wennemers |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
chemistry.chemical_classification
biology 010405 organic chemistry Stereochemistry Organic Chemistry Substrate (chemistry) chemistry.chemical_element Cinchona 010402 general chemistry biology.organism_classification Thioester 01 natural sciences 3. Good health 0104 chemical sciences Stereocenter chemistry Nitro Organic chemistry Stereoselectivity Carbon Conjugate |
| Zdroj: | The Journal of organic chemistry |
| ISSN: | 1520-6904 0022-3263 |
| Popis: | A method for the stereoselective synthesis of acyclic thioesters bearing adjacent quaternary and tertiary stereogenic centers under mild organocatalytic conditions was developed. α-Substituted monothiomalonates (MTMs) were used as thioester enolate equivalents. They reacted cleanly with nitroolefins in the presence of 1-6 mol % of cinchona alkaloid urea derivatives, and provided access to γ-nitrothioesters with quaternary stereocenters in high yields and diastereo- and enantioselectivities. Mechanistic investigations provided insight into the parameters that determine the stereoselectivity and showed that the diastereoselectivity can be controlled by the nature of the MTM substrate. The different reactivities of the three functional groups (oxoester, thioester, nitro moieties) within the conjugate addition products allowed for straightforward access to other compounds with quaternary stereogenic centers, such as γ-nitroaldehydes and γ-butyrolactams. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|