Copper-Assisted/Copper-Free Synthesis of Functionalized Dibenzo[ b, f]oxepins and Their Analogs via a One-Pot Tandem Reaction.

A simple, convenient, and efficient method for the formation of functionalized dibenzo[ b, f]oxepins and their analogs bearing both electron-donating and electron-withdrawing groups has been developed via a one-pot cascade reaction. Most starting materials are commercially available 2-(2-hydroxyphenyl)acetonitriles and 2-haloarylaldehydes. The procedure makes use of Cs₂CO₃ as the base, and DMF as solvent under copper-assisted/copper-free conditions. The reaction has a comprehensive group tolerance for substrates. Most of the reactions were complete within 1 h in good-to-excellent yields, and the reaction temperatures were relatively low. The protocol could be scaled up to grams without lowering the yield. A reaction mechanism was also proposed. [ABSTRACT FROM AUTHOR]