The Importance of 1,5-Oxygen center dot center dot Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis
The importance of 1,5-O center dot center dot center dot chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N-acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5-O center dot center d...
Saved in:
Published in | Angewandte Chemie International Edition Vol. 59; no. 9; pp. 3705 - 3710 |
---|---|
Main Authors | , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
WEINHEIM
Wiley
24.02.2020
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | The importance of 1,5-O center dot center dot center dot chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N-acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5-O center dot center dot center dot Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal [4+2] cycloadditions. A gram-scale synthesis of the most active selenium analogue was developed using a previously unreported seleno-Hugerschoff reaction, allowing the challenging kinetic resolutions of tertiary alcohols to be performed at 500 ppm catalyst loading. Density functional theory (DFT) and natural bond orbital (NBO) calculations support the role of orbital delocalization (occurring by intramolecular chalcogen bonding) in determining the conformation, equilibrium population, and reactivity of N-acylated intermediates. |
---|---|
Bibliography: | UKRI |
ISSN: | 1433-7851 1521-3773 |
DOI: | 10.1002/anie.201914421 |