Synthesis of γ-Spirolactams via Rh(III)-Catalyzed C-H Activation/Directing Group Migration/Dearomatization/Spiroannulation of Indoles with 1,3-Enynes.

1,3-Enynes are valuable coupling partners in transition-metal-catalyzed C-H functionalizations. Certainly, aliphatic-substituted 1,3-enynes have been thoroughly investigated in C-H functionalizations, whereas aromatic-substituted 1,3-enynes remain underexplored. Herein, we report the realization of this goal, where we achieve an atom-economical protocol for the synthesis of γ-spirolactams via Rh(III)-catalyzed C-H functionalization of N -carbamoylindoles with 1,3-enynes. The reaction proceeds through a unique cascade strategy, such as C-H activation/directing group (DG) migration/indole dearomatization/spiroannulation, to access novel and synthetically challenging spiro[indoline-2,2'-pyrrolidin]-5'-one scaffolds. Moreover, the isolation of intermediate and mechanistic and ESI-HRMS studies further provide valuable insights into the proposed catalytic cycle.