Gold or No Gold: One-Pot Synthesis of Tetrahydrobenz[b]azepin-4-ones from Tertiary N-(But-3-ynyl)anilines

Depending on the tertiary aniline substrates, an efficient, one-pot synthesis of tetrahydrobenz[b]azepin-4-ones needs either gold catalysts or no catalyst at all. In the reaction, the aniline nitrogen plays a unique role in relaying O from m-CPBA to a tethered C-C triple bond, which is inert to the oxidant under the mild reaction conditions.