Synthesis of 1(2H)-isoquinolones by the nickel-catalyzed denitrogenative alkyne insertion of 1,2,3-benzotriazin-4(3H)-ones.

1,2,3-Benzotriazin-4(3H)-ones reacted with internal and terminal alkynes in the presence of a nickel(0)/phosphine catalyst to give a wide range of substituted 1(2H)-isoquinolones in high yield. The reaction proceeded through denitrogenative activation of the triazinone moiety and the following insertion of alkynes.