Ruthenium‐Catalyzed Decarboxylative Rearrangement of 4‐Alkenyl‐isoxazol‐5‐ones to Pyrrole Derivatives

Easily accessible isoxazol‐5(4H)‐ones are useful precursors of heterocycles. In this context, we report the ruthenium‐catalyzed transformation of 4‐alkenyl‐substituted isoxazol‐5‐ones to afford 1H‐pyrrole derivatives. The operative conditions were proven to be effective also on cyclohexane‐fused isoxazolones giving 4,5,6,7‐tetrahydroindoles. The reactions, which allow for access to tri‐and tetra‐substituted pyrroles in moderate to high yields, occur through decarboxylative ring‐opening/ring‐closure involving C−H functionalization of the alkenyl moiety.