Brønsted acid catalyzed enantioselective addition of hydrazones to 3-indolylmethanols

Abstract

The organocatalytic asymmetric addition of hydrazones to indole derivatives in the presence of chiral Brønsted acids is reported. A large variety of substrates are tolerated and the products are obtained in good yields and with excellent enantioselectivities. This metal-free reaction provides a convenient route to enantiopure β-substituted tryptophan derivatives in a concise fashion.