Remarkable influence of mild Lewis acid catalysts on cycloadditions leading to tetrasubstituted isoxazolidines: DFT analysis augmented by X-ray and NMR studies
Experimental and theoretical studies were carried out to highlight the influence of mild Lewis acid catalysts on the cycloadditions leading to stereochemically defined tetrasubstituted isoxazolidines. Considerable acceleration and increased exo stereoselectivity were observed for lithium triflate an...
Saved in:
Published in | Monatshefte für Chemie Vol. 143; no. 12; pp. 1687 - 1703 |
---|---|
Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Vienna
Springer Vienna
01.12.2012
Springer Nature |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Experimental and theoretical studies were carried out to highlight the influence of mild Lewis acid catalysts on the cycloadditions leading to stereochemically defined tetrasubstituted isoxazolidines. Considerable acceleration and increased
exo
stereoselectivity were observed for lithium triflate and magnesium bromide catalyzed processes. DFT-based reactivity indices reflected the differences in polar character of the catalyzed and uncatalyzed pathways. The regioselectivities were predicted from interaction energy calculations. Finally, the transition states were successfully located and the extent of bond formation analyzed. The catalytic acceleration was rationalized by density functional theory (DFT) calculated activation parameters. The rate constant ratios with Eyring’s transition state theory (TST) rate equation and total partition functions were also theoretically evaluated to further rationalize the observed catalytic acceleration.
Graphical abstract |
---|---|
ISSN: | 0026-9247 1434-4475 |
DOI: | 10.1007/s00706-012-0828-z |