AgO-mediated Tandem Reaction between Terminal Alkyne and -Iodibenzoic Acid: Construction of 3-Ethylideneisobenzofuran-1(3)-ones.

Taking aryl propargyl ether and -iodibenzoic acid as substrates, a series of aryl cyclolactones bearing an exocyclized C=C bond were constructed with moderate to good yields. Diverse substituent groups could be tolerant in the reaction, which indicated excellent compatibility of the reaction. In this tandem reaction, AgO was employed as the media and EtN was screened as the base to facilitate the reaction. A concise mechanism was proposed on the basis of the expansion of the substrates and theoretical analysis. Sonogashira type coupling coupled with intramolecular nucleophilic addition in one pot to construct the product, 3-ethylideneisobenzofuran-1(3)-one.