Acid‐Promoted Carbon‐Carbon Triple Bond Cleavage of Ynones for the Synthesis of Benzo[d]oxazoles/Benzo[d]thiazoles and 1‐Arylethan‐1‐ones

Abstract A synchronous synthesis of benzo[ d ]oxazoles/benzo [ d ]thiazoles and 1‐arylethan‐1‐ones enabled by acid‐promoted C−C triple bond cleavage of ynones is disclosed. This reaction was accomplished with good tolerance of various functional groups and aminophenols/aminobenzenethiols to access the corresponding products, especially some structurally special 1‐arylethan‐1‐ones, in moderate to good yield. Furthermore, the readily accessible synthesis of some biologically active molecules has highlighted the synthetic utility of this strategy.