Regio‐ and Stereoselective Synthesis of (<i>Z</i>)‐<scp>3‐Ylidenephthalides</scp><i>via</i><scp>H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub>‐Catalyzed</scp> Cyclization of <scp>2‐Acylbenzoic</scp> Acids with Benzylic Alcohols
Guo‐Ping Yang, Ke Li, Xiaoling Lin, Yijin Li, Cheng‐Xing Cui, Shixiong Li, Yuanyuan Cheng, Yufeng Liu
Abstract
Main observation and conclusion We report an exclusively tandem C—O and C—C bond forming beyond the esterification and cyclization reaction of 2‐acylbenzoic acids with alcohols to regio‐ and stereoselective synthesis of the ( Z )‐3‐ylidenephthalides. The reaction uses the nontoxic, inexpensive H 3 PMo 12 O 40 as catalyst and produces water as the sole by‐product, making the reaction environmentally benign and sustainable. Moreover, this reaction features an eco‐friendly reaction condition, facile scalability, and easy derivatization of the products to drugs and bioactive compounds. The mechanism studies and density functional theory calculations reveal that the appropriate acid catalyst is the key to the selectivity of this transformation.