Pd(II)/LA‐Catalyzed Intramolecular Hydroarylation of Alkynoates to Construct Coumarins

Transition‐metal ions catalyzed intramolecular hydroarylation of aryl alkynoates to construct coumarin skeletons is merited for its step and atom‐economic advantages when compared with other methodologies. The challenge is that the electrophilic cyclization of this reaction requires the strong electrophilic capability of the catalyst, which makes this methodology was seldomly developed after its early explorations. Herein, we report a Lewis acid promoted Pd(II)‐catalyzed intramolecular hydroarylation to construct coumarin and its derivatives; the linkage of Lewis acid to the Pd(II) species through diacetate bridge improved its electrophilic capability, facilitating the hydroarylation reaction happening under the neutral conditions.