Pd-Catalyzed Assembly of Spirooxindole Natural Products: A Short Synthesis of Horsfiline

The Pd-catalyzed intramolecular alpha-arylation of amides is applied to the synthesis of functionalized spirooxindoles. The substrate scope is evaluated, and the reaction is demonstrated to be useful for the assembly of spirooxindole natural products and derivatives thereof. As an application, a new synthesis of horsfiline 1 is presented, giving the natural product in only 4 steps from commercially available amino acid 12.