Ni-Catalyzed Synthesis of 4-Quinolones from Alkynes and Isatoic Anhydrides

Significance

The synthesis of 4-quinolones 3 is reported via the Ni-catalyzed decarboxylative carboamination of alkynes 2 with isatoic anhydrides 1. The reaction is tolerant of a range of R^¹ substituents, including alkyl, acyl and both electron-rich and electron-poor aryl groups. A variety of alkynes may also be used. Unsymmetrical alkynes gave mixtures of the two possible regioisomers (ratio from 2:1 to 6:1), where the larger group is placed preferentially at C-3, most likely due to steric repulsion between the larger alkyne substituent (R⁴) and the Ni ligand (see scheme).