Highly Efficient InBr 3 Catalyzed Michael Addition of Indoles to α , β ‐Unsaturated Esters

A highly efficient synthetic strategy toward Michael addition of indoles to α , β ‐unsaturated esters has been developed using Lewis acid InBr 3 as catalyst. The reactions generated 3‐substituted indoles in high yields with excellent regio‐selectivity in the presence of catalytic amount of InBr 3 under mild reaction conditions. The method is simple, efficient and practical.