Multi-site cyclization via initial C-H activation using a rhodium(III) catalyst: rapid assembly of frameworks containing indoles and indolines.

Tandem multi-site cyclization triggered by Rh(III)-catalyzed C-H activation has been achieved for highly efficient synthesis of spirocycle indolin-3-one (C2-cyclization), benzo[a] carbazole (C3-cyclization) and an unusual indoxyl core (N1-cyclization). In particular, the synthesis of pseudo-indoxyl is typically completed within 10 min, and the reaction tolerates air, water and a range of solvents.