Palladacycle-catalyzed decarboxylative coupling of alkynyl carboxylic acids with aryl chlorides under air.J Org Chem. 2013 May 03; 78(9):4543-50.JO
A highly efficient and practical protocol for palladacycle-catalyzed decarboxylative coupling of alkynyl carboxylic acids with aryl chlorides was developed. The reaction could proceed smoothly in air within 3 h under optimized reaction conditions (1 mol % of palladacycle, 4 mol % of Xphos, 2.0 equiv of K2CO3 in xylene/H2O), affording the corresponding internal alkynes in mostly good to excellent yields. Remarkably, this result represents the first successful examples of this type of decarboxylative cross-coupling using electron-poor, electron-neutral and even inactive sterically hindered electron-rich aryl chlorides as the starting materials.