1,3-Bis(N,N-dialkylamino)imidazolin-2-ylidenes: synthesis and reactivity of a new family of stable N-heterocyclic carbenes.
The synthesis of stable 1,3-bis(N,N-dialkylamino)imidazolin-2-ylidenes was accomplished from readily available chiral bis-hydrazones after reduction or addition of PhMgCl, cyclization to imidazolinium salts, and treatment with KN(SiMe3)2. This strategy allows the obtention of free imidazolin-2-ylidenes and their Rh(COD)Cl complexes in enantiomerically pure form. The sigma-donor ability of dialkylamino-substituted diaminocarbenes was found to be slightly higher than that of alkyl(aryl) analogues.
Instituto de Investigaciones Químicas (CSIC-US), C/Américo Vespucio s/n, Isla de la Cartuja, E-41092 Seville, Spain.
Manuel
M
Alcarazo
Stephen J
SJ
Roseblade
Emma
E
Alonso
Rosario
R
Fernández
Eleuterio
E
Alvarez
Fernando J
FJ
Lahoz
José M
JM
Lassaletta