Sulfoxide-Based Functionalization of Tryptophan Derivatives through Sulfenylation and Selenylation

A sulfoxide-based modification of tryptophan derivatives has been established through sulfenylation and selenylation, affording various highly functionalized tryptophan derivatives of great interest in acceptable-to-good yields. Sequential sulfenylation and bromination occur at the C2 and C6 positions of tryptophan derivatives, respectively, under an AcBr/TMSO/thiol reaction system. In contrast, only selenylation can be realized at the C2 position of tryptophan derivatives by the use of AcCl/DMSO and RSeSeR.