Direct Access to 9-Chloro-1 H -benzo[ b ]furo[3,4- e ]azepin-1-ones via Palladium(II)-Catalyzed Intramolecular syn -Oxypalladation/Olefin Insertion/sp 2 -C-H Bond Activation Cascade

An efficient Pd(II)-catalyzed cascade approach was established for the synthesis of 9-chloro-1 -benzo[ ]furo[3,4- ]azepin-1-ones starting from -propargyl arylamines having a pendant α,β-unsaturated ester scaffold. The mechanism of this sequential process involved intramolecular -oxypalladation followed by olefin insertion and sp -C-Cl bond formation reactions. This high atom- and step-economical cascade sequence generated two heterocycle rings and three new bonds in a single synthetic operation.