Anders, Ernst; Opitz, Andreas; Boese, Roland:
The first x-ray structures of N-lithiated 4-alkylidene-1,4-dihydropyridines [{4-(CH3CR)C5H4N}Li(TMEDA)]2: comparison of the x-ray and MNDO geometries and investigation of lithium coordination in solution.
1992
In: Chemische Berichte (Chem.Ber.), Jg. 125 (1992), Heft 5, S. 1267 - 1271
Artikel/Aufsatz in Zeitschrift1992Chemie
Titel:
The first x-ray structures of N-lithiated 4-alkylidene-1,4-dihydropyridines [{4-(CH3CR)C5H4N}Li(TMEDA)]2: comparison of the x-ray and MNDO geometries and investigation of lithium coordination in solution.
Autor(in):
Anders, Ernst; Opitz, Andreas; Boese, RolandLSF
Erscheinungsjahr
1992

Abstract:

4-Ethyl- and isopropylpyridine reacted with LDA and TMEDA to give title compds. I (R = H, Me), which were subjected to x-ray anal. The structural parameters of the heterocyclic moieties of I are typical of N-lithiated 4-alkylidene-1,4-dihydropyridines. MNDO geometries compare quite well with x-ray structure of I (R = H). The lithium atom of I (R = H) in soln. prefers the same type of coordination as in the crystal. Two-dimensional 6Li,1H-HOESY showed Li contacts only to ortho-hydrogen atoms. I (R = H) reacts exclusively as a C nucleophile, whereas I (R = Me) reacts exclusively as a N nucleophile.