Cooperative Gold/Zinc‐Catalyzed Cascade Approach to Tryptophan Derivatives from N‐arylhydroxylamines and Alkynes

Abstract

A cooperative gold/zinc catalyzed strategy for the synthesis of tryptophan derivatives from easily prepared N‐arylhydroxylamines and chiral amino acid tethered alkynes with high efficiency has been developed. The structurally diverse tryptophan derivatives including pharmaceutical relevant molecules can be readily prepared by this method. This tandem transformation starts from acyclic simple materials rather than the existing methods by modifying indole skeletons.

Recent Progress in Gold‐Catalyzed Reactions of Alkynes for the Construction of Indole Frameworks

“…Gao's group employed amino acid tethered alkynes 154 to react with arylhydroxylamines 155 enabled by cooperative gold/zinc dual catalysis. [103] The strategy delivered structurally diverse tryptophan derivatives 156 in high yields with impressive enantioselectivity (up to 94% ee). The reaction was supposed to proceed via the formation of O-alkenylated arylhydroxylamine species 157, which would experience [3,3]-sigmatropic rearrangement to afford target tryptophan compounds (Scheme 40).…”