Reactivity of an Oxalamid-Based N-Heterocyclic Carbene

The reactivity of the oxalamide-based carbene 2 was investigated. Treatment with styrene or methylacrylate proceeded under carbene addition to yield the respective cyclopropanation products 6a,b. With elemental selenium, I the selenide 7 was obtained, which was characterized by X-ray diffraction. The Rh complex [(COD)RhC1(2)] (10) was also structurally characterized. From the IR spectrum of the dicarbonyl derivative [(CO)(2)RhC1(2)] (11) a Tolman electronic parameter of 2068 cm(-1) was calculated for the diamidocarbene 2, which characterizes this ligand as the least electron donating NHC known so far. The dimerization product of carbene 2, the intensly fluorescing tetraamido ethylene 3, showed an unexpected chemical stability. Treatment of the chloro compound la with methanol afforded the methoxide 5a, whose structure was determined by X-ray diffraction.