Synthesis of Both Enantiomers of Nine‐Membered CF 3 ‐Substituted Heterocycles Using a Single Chiral Ligand: Palladium‐Catalyzed Decarboxylative Ring Expansion with Kinetic Resolution
| Autor: | Motoo Shiro, Hiroto Uno, Etsuko Tokunaga, Norio Shibata, Nagender Punna |
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| Rok vydání: | 2020 |
| Předmět: |
Chiral auxiliary
Trifluoromethyl 010405 organic chemistry Decarboxylation Chiral ligand chemistry.chemical_element General Chemistry 010402 general chemistry 01 natural sciences Medicinal chemistry Catalysis 0104 chemical sciences Kinetic resolution chemistry.chemical_compound chemistry Enantiomer Palladium |
| Zdroj: | Angewandte Chemie International Edition. 59:8187-8194 |
| ISSN: | 1521-3773 1433-7851 |
| DOI: | 10.1002/anie.201915021 |
| Popis: | The two enantiomers of trifluoromethyl-benzo[c][1,5]oxazonines, (R)-4 and (S)-4, can be selectively accessed with high enantiopurity by the Pd-catalyzed ring-expansion reaction of trifluoromethyl-benzo[d][1,3]oxazinones (1) with vinyl ethylene carbonates (3) using one antipode of a chiral ligand. Initially, the reaction proceeds by a double decarboxylative ring-expansion with kinetic resolution of 1 in the presence of a Pd-catalyst/chiral ligand to provide (R)-4 with high enantiopurity. At the same time, the nonreactive antipode of 1, (S)-1, which was recovered with an impeccable s factor of up to 713 and an ideal chemical yield, was transferred into the antipode of the products, (S)-4, with high enantiopurity by a second run of the Pd-catalyzed double decarboxylation reaction, but this time without any chiral auxiliary. Thus, both antipodes of the chiral trifluoromethyl heterocycles 4 can be obtained in excellent enantiopurity using only a single antipode of the chiral catalyst. |
| Databáze: | OpenAIRE |
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