Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to Indolylnitroalkenes

Indolylnitroethanes and their derivatives are key intermediates to many bioactive structures. Most approaches to access chiral indolylnitroethanes involve organocatalyzed or metal‐catalyzed asymmetric Friedel–Crafts reaction of indoles with nitroalkenes. We have developed an efficient approach to optically pure α‐aryl‐3‐indolylnitroethanes through rhodium‐catalyzed asymmetric 1,4‐addition of arylboronic acids to indolylnitroalkenes. Excellent yields (up to 99 %) and enantiomeric excesses (up to 99 % ee) of chiral indolylnitroethanes were achieved under mild conditions. An efficient approach to optically pure α‐aryl‐3‐indolylnitroethanes through rhodium‐catalyzed asymmetric 1,4‐addition of arylboronic acids to indolylnitroalkenes was developed. Excellent yields (up to 99 %) and enantiomeric excesses (up to 99 %) were achieved under mild conditions.