A Pd[0]-catalyzed Ullmann cross-coupling/reductive cyclization approach to C-3 mono-alkylated oxindoles and related compounds

The Pd[0]-catalyzed Ullmann cross-coupling of o-nitrohaloarenes 1a–e with the brominated heterocycles 2a–f delivers the expected products 3a–j in good to excellent yields. The reductive cyclization of such products, as well as N-acyl derivatives 3k, l, and m, has been investigated and provided the C-3 mono-substituted oxindoles 5a–d, f, g, k, and m, the direct reduction products 4i and j or indole 5l.