Palladium‐Catalyzed Synthesis of 6 H ‐Dibenzo[ c,h ]chromenes and 5,6‐Dihydrobenzo[ c ]phenanthridines: Application to the Synthesis of Dibenzo[ c,h ]chromene‐6‐ones, Benzo[ c ]phenanthridines, and Arnottin I

6 H ‐Dibenzo[ c,h ]chromenes and 5,6‐dihydrobenzo[ c ]phenanthridines have been synthesized via Palladium (II)‐catalyzed domino reactions of acetylenic substrates involving intramolecular trans ‐oxo/amino palladation onto the triple bond followed by nucleophilic addition of the intermediate to a tethered cyano/aldehyde. The scope of this reaction was extended through one step conversion of some of the products to 6 H ‐dibenzo[ c,h ]chromen‐6‐ones and benzo[ c ]phenanthridines. Utilization of this methodology led to a formal total synthesis of the natural product Arnottin I .