Dynamics in Catalytic Asymmetric Diastereoconvergent (3 + 2) Cycloadditions with Isomerizable Nitrones and α-Keto Ester Enolates
| Autor: | Masaya Adachi, Hiroyuki Koshino, Mai Akakabe, Tetsuya Ezawa, Mikiko Sodeoka, Daisuke Hashizume, Yoshihiro Sohtome |
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| Rok vydání: | 2021 |
| Předmět: |
chemistry.chemical_classification
Stereochemistry Enantioselective synthesis Diastereomer General Chemistry 010402 general chemistry 01 natural sciences Biochemistry Catalysis Transition state 0104 chemical sciences Stereocenter Nitrone Colloid and Surface Chemistry Syn and anti addition Deprotonation chemistry |
| Zdroj: | Journal of the American Chemical Society. 143:9094-9104 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.1c02833 |
| Popis: | Reaction design in asymmetric catalysis has traditionally been predicated on a structurally robust scaffold in both substrates and catalysts, to reduce the number of possible diastereomeric transition states. Herein, we present the stereochemical dynamics in the Ni(II)-catalyzed diastereoconvergent (3 + 2) cycloadditions of isomerizable nitrile-conjugated nitrones with α-keto ester enolates. Even in the presence of multiple equilibrating species, the catalytic protocol displays a wide substrate scope to access a range of CN-containing building blocks bearing adjacent stereocenters with high enantio- and diastereoselectivities. Our computational investigations suggest that the enantioselectivity is governed in the deprotonation process to form (Z)-Ni-enolates, while the unique syn addition is mainly controlled by weak noncovalent bonding interactions between the nitrone and ligand. |
| Databáze: | OpenAIRE |
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