Synthesis of Highly Substituted 2-Aminopyridines with Vinyl Azides, Isonitriles, and Ketones.

We developed a facile, efficient method for synthesizing highly substituted 2-aminopyridines from unstable vinyl carbodiimides generated in situ in a one-pot transformation. A series of novel highly substituted 3-functionalized 2-aminopyridines were produced in good yields. Reaction mechanism studies, which included control experiments and density-functional theory (DFT) calculations, demonstrated that Rh and potassium carbonate played key roles in the cyclization step.