Structural and Synthetic Insights into Pyridine Homocouplings Mediated by a ß-Diketiminato Magnesium Amide Complex.
Chemistry
; 24(55): 14830-14835, 2018 Oct 01.
Article
in En
| MEDLINE
| ID: mdl-30051933
ABSTRACT
The reaction of [(Dipp Nacnac)Mg(TMP)] (1) with 4-subtituted pyridines proceeds via sequential regioselective metallation and 1,2-addition to furnish a range of symmetric 4,4'-R2 -2,2'-bipyridines in good yield, representing a new entry into bipyridine synthesis. Interestingly, the reaction of 1 with 2-OMe-pyridine led to formation of asymmetric bipyridine 6, resulting from the C6-magnesiation of the heterocycle followed by a C-C coupling step by addition to the C2 position of a second, non-metallated molecule, and subsequent elimination of [Dipp NacnacMgOMe]2 (7). Synthesis combined with spectroscopic and structural analysis help rationalise the underlying processes resulting in the observed reactivity, and elucidate the key role that the sterically encumbered ß-diketiminate ligand plays in determining regioselectivity.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Chemistry
Journal subject:
QUIMICA
Year:
2018
Type:
Article
Affiliation country:
United kingdom