Abstract
One way to build chemical diversity into indoles is to oxidize them to indolyl radical cations (Ind(•+)). These intermediates can accept new functional groups across C2-C3 bonds or independently at C2. Less encountered is selective diversification at C3, a position plagued by competing dearomative side reactions. We disclose an aqueous photoredox-catalyzed method for transforming Ind(•+) into C3-substituted tryptophan mimetics that uses water as a transient protecting group to guide site-selective C3 alkylation.