Influence of pyrido-annulation on N,N′-dineopentyl-imidazolin-2-ylidene and associated transition metal complexes; comparison with benzo-, naphtho- and quinoxalino-annulation

The syntheses of isolable N,N′-dineopentyl-substituted non- and pyrido-annulated imidazolin-2-ylidenes and selected Ag, Rh and Pd complexes thereof, in part earlier communicated, are now reported in full detail. The compounds were structurally characterized by multinuclear NMR and in part by crystal structure analyses. Diagnostic structural and NMR data were compared with those of analogously N,N′-dineopentyl-substituted benzo-, naphtho- and quinoxalino-annulated compounds, and the influence of the annulation was tested by L/Pd-and L2/Pd-catalyzed Suzuki-Miyaura couplings of PhB(OH)2 with p-bromotoluene.