Synthesis of isochroman-4-ones and 2H-pyran-3(6H)-ones by gold-catalyzed oxidative cycloalkoxylation of alkynes.

Gold catalysis is a convenient tool to oxidatively functionalize alkyne into a range of valuable compounds. In this article, we report a new access to isochroman-4-one and 2H-pyran-3(6H)-one derivatives that involves a gold-catalyzed oxidative cycloalkoxylation of an alkyne in the presence of a pyridine N-oxide. The reaction proceeds under mild conditions, is relatively efficient and exhibits a high functional group compatibility.