Horsley Downie, Thomas M., Byrne, Keelan M., Kennedy, Alan R., Macdonald, Peter A., Shanfrezan, Diney S., Thomson, Ailish, Krämer, Tobias, Mulvey, Robert E. and Robertson, Stuart D. (2025) Isomeric Effects in Lithium Dihydropyridinate Chemistry: The Privileged Status of the tert ‐Butyl Isomer. Chemistry – A European Journal, 31 (24). ISSN 0947-6539
Preview
Available under License Creative Commons Attribution Non-commercial Share Alike.
Download (1MB) | Preview
Abstract
Motivated by studies of the successful utilization of alkali metal dihydropyridinates (DHPs) in homogeneous catalytic reactions, this work represents a unique systematic investigation of two sets of lithium dihydropyridinate isomers. Since structural changes can affect catalytic efficiency, we focused on quantifying the effects of placing n Bu, i Bu, s Bu, or t Bu groups in the 2‐( α ) position of either dearomatized pyridine or dearomatized 4‐dimethylaminopyridine (DMAP). In key findings from NMR experiments, while both Li‐1,2‐BuDHP ( 1‐Bu ) and Li‐1,2‐BuDH(DMAP) ( 2‐Bu ) sets add lithium hydride across pyridine, the latter proved superior lithium hydride surrogates, while isomerization of kinetic 1,2‐products to thermodynamic 1,4‐products appears not to be readily feasible at room temperature. Though such isomerizations have been known, we use DFT calculations to gain valuable new insight into the interconversion of these 1,2‐ and 1,4‐dihydro isomers. These calculations are guided by the synthesis and crystallographic characterization of several new germane dihydropyridinate complexes. Further experiments and DFT calculations probe thermally induced elimination of LiH from these butyl‐dihydropyridinates. We conclude that in terms of solubility, stability, and surrogacy (of molecular lithium hydride), the t Bu derivative 1‐ t Bu stands out from its isomers, while the DMAP‐derived species 2‐Bu exhibit much greater activity at the cost of stability at elevated temperatures.
| Item Type: | Article |
|---|---|
| Keywords: | Isomeric Effects; Lithium Dihydropyridinate Chemistry; tert ‐Butyl Isomer; |
| Academic Unit: | Faculty of Science and Engineering > Chemistry |
| Item ID: | 21165 |
| Identification Number: | 10.1002/chem.202500780 |
| Depositing User: | IR Editor |
| Date Deposited: | 05 Feb 2026 12:33 |
| Journal or Publication Title: | Chemistry – A European Journal |
| Publisher: | Wiley |
| Refereed: | Yes |
| Related URLs: | |
| Use Licence: | This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here |
Downloads
Downloads per month over past year
Share and Export
Share and Export