γ‐, Diastereo‐, and Enantioselective Addition of MEMO‐Substituted Allylboron Compounds to Aldimines Catalyzed by Organoboron–Ammonium Complexes
| Autor: | Ryan J. Morrison, Amir H. Hoveyda |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Boron Compounds
Models Molecular Aldimine 010402 general chemistry 01 natural sciences Article Catalysis chemistry.chemical_compound Ammonium Compounds Phosphorylation Protecting group chemistry.chemical_classification 010405 organic chemistry Aryl Enantioselective synthesis Diastereomer Stereoisomerism General Chemistry Combinatorial chemistry 0104 chemical sciences Allyl Compounds chemistry Catalytic cycle Imines Enantiomer Selectivity |
| Zdroj: | Angewandte Chemie International Edition. 57:11654-11661 |
| ISSN: | 1521-3773 1433-7851 |
| DOI: | 10.1002/anie.201805811 |
| Popis: | The first catalytic, broadly applicable, efficient, γ-, diastereo-, and enantioselective method for addition of O-substituted allyl–B(pin) compounds to phosphinoylimines (MEM = methoxyethoxymethyl, pin = pinacolato) is presented. The identity of the most effective catalyst and the optimal protecting group for the organoboron reagent were determined by consideration of the steric and electronic requirements at different stages of the catalytic cycle, namely, the generation of the chiral allylboronate, the subsequent 1,3-borotropic shift, and the addition step. Aryl-, heteroaryl-, alkenyl- and alkyl-substituted vicinal phosphinoylamido MEM-ethers were thus accessed in 57–92% yield, 89:11 to >98:2 γ:α selectivity, 76:24–97:3 diastereomeric ratio, and 90:10–99:1 enantiomeric ratio. The method is scalable, and the phosphinoyl and MEM groups may be removed selectively or simultaneously. Utility is highlighted by enantioselective synthesis of an NK-1 receptor antagonist. |
| Databáze: | OpenAIRE |
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