Metal-Free Late-Stage Alkylation of Tryptophan and Tryptophan-Containing Peptides with 1,3-Dithiane Derivatives

Late-stage diversification of structurallycomplex peptides hasenormous potential for drug discovery and molecular imaging. We reporta simple, metal-free, late-stage reductive C2 alkylation of tryptophanand tryptophan-containing peptides using readily available 1,3-dithianes.This alkylation protocol has a wide substrate scope and an excellenttolerance for reactive functional groups.