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. Access to highly substituted 2‐aminopyridines by one‐pot transformation of vinyl azides, isonitriles, and 1,3‐dicarbonyl compounds via unstable vinyl carbodiimides and five‐membered rhodacycle intermediates is reported.