Cobalt-Catalyzed\nIntramolecular Enantioselective Reductive\nHeck Reaction toward the Synthesis of Chiral 3‑Trifluoromethylated\nOxindoles

Herein, a cobalt-catalyzed intramolecular enantioselective\nreductive\nHeck reaction is disclosed. Starting from <i>N</i>-<i>ortho</i>-iodoaryl-2-(trifluoromethyl)acrylamides, a plethora\nof chiral oxindoles bearing trifluoromethylated quaternary stereogenic\ncenters at the C3-position are achieved in moderate to good yields\n(up to 88% yield) and good to excellent enantioselectivities (up to\n94% ee) by employing zinc/silane as reducing agent. Other than the\ntrifluoromethyl group, a number of chiral oxindoles bearing alkyl,\naryl, and ester groups at C3-position were also obtained albeit in\nrelatively lower enantioselectivities (68–78% ee).