Modular Catalytic Synthesis of 3-Amino-3-aryl-2-oxindoles: Rh Catalysis with Isatin-Derived N-Boc-Protected Ketimines

Chiral 3‐amino‐3‐aryloxindoles are important biologically active compounds. Using a catalytic modular approach, 31 new 3‐amino‐3‐aryl‐2‐oxindoles were prepared by a simple Rh‐catalysed addition of arylboronic acids to isatin‐derived N‐Boc‐protected ketimines (Boc = tert‐butoxycarbonyl). A low catalyst loading of 3 mol‐% was used, and the reaction showed a wide scope with high functional‐group compatibility, and gave good yields. We report the first catalytic enantioselective reactions with this substrate. Deprotection of the Boc group was easily accomplished in good yields. A general and economically viable route for the synthesis of 3‐amino‐3‐aryl‐2‐oxindole compounds was accomplished through the Rh‐catalysed addition of arylboronic acids to isatin‐derived N‐tert‐butoxycarbonyl‐protected ketimines.