Rh(II)-catalyzed Doyle–Kirmse reaction: Access to unprotected 3-allyl/3-allenyl-3-(thio)oxindoles

The construction of the 3-allyl/3-allenyl-3-(thio)oxindole core remains a challenge in organic synthesis. Herein, we report a novel Rh2(esp)2 catalytic Doyle-Kirmse reaction to furnish the oxindole core, bearing unbiased NH as well as a quaternary stereogenic center at the 3-position, in good to excellent yields under mild conditions. These reactions are concise, practical, atom-economic, and highly efficient, and feature a TON of up to 3700. Moreover, a non-radical pathway was observed in this approach.