Ring lithiation and functionalization of imidazol-2-ylidene-boranes.
N,N'-dialkyl and N,N'-diaryl imidazol-2-ylidene-boranes and trifluoroboranes are rapidly lithiated at C4 of the imidazole ring, and the resulting intermediates have been quenched with an assortment of electrophiles to provide ring-functionalized imidazol-2-ylidene-boranes. Further deprotonation and functionalization of C5 have been demonstrated. Deboronation of the products by treatment with triflic acid or iodine and then methanol opens a route to C4/C5 functionalized imidazolium salts and imidazol-2-ylidenes.
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
Andrey
A
Solovyev
Emmanuel
E
Lacôte
Dennis P
DP
Curran