A (salen)­Mn­(III) complex was used as a biomimetic surrogate of the metallocofactor of phenol-oxidizing enzymes, in combination with chiral phosphoric acid relay catalysis, enabling an enantioselective direct oxidative phenol-indole [3 + 2] coupling reaction to access structurally diverse chiral benzofuroindolines. Differing from previous methods that exclusively make use of isolatable quinones or their imines, this system is capable of harnessing transient N-Boc quinone imines, and highlights its synthetic potential with high enantioselectivities, high step and atom economy, benign reaction conditions, and remarkable catalytic turnover for chiral phosphoric acid (CPA) (low to 0.01 mol %; up to 4100 turnover number (TON)).

Inspired by mechanic force induced S–S bridge activation in a protein context, we have developed the first mechanochemical electrophilic C–H sulfenylation of indoles in combination with iodine catalysis. Differing from previous relevant methods that typically necessitate either intrinsically reactive sulfur sources or external forceful conditions but at the expense of atom economy and environmental benignity, our strategy disclosed herein capitalizes on readily available disulfides as sulfenylation reagents promoted by ball milling, thereby rendering rapid synthesis of indolyl sulfides with broad structural diversity under aerobic oxidation and solvent-minimum and metal-free conditions. Moreover, mechanistic studies reveal that the solid and liquid grinding auxiliaries synergistically facilitate this process.

The activation of disulfides by Cu(II) salts has been realized, which triggers a highly efficient electrophilic sulfenoamination of alkenes under aerobic conditions. Various sulfenyl N-heterocycles and their Selena counterparts were produced regioselectively, with no competing disulfidation products detected. Mechanistic studies suggest a profound influence of the counterions on the Lewis acidic copper center, and the important roles of oxygen and DMSO as co-oxidants for these cyclization processes.

Reported here is the first catalytic atroposelective electrophilic amination of indoles, which delivers functionalized atropochiral N-sulfonyl-3-arylaminoindoles with excellent optical purity. This reaction was furnished by 1,6-nucleophilic addition to p-quinone diimines. Control experiments suggest an ionic mechanism that differs from the radical addition pathway commonly proposed for 1,6-addition to quinones. The origin of 1,6-addition selectivity was investigated through computational studies. Preliminary studies show that the obtained 3-aminoindoles atropisomers exhibit anticancer activities. This method is valuable with respect to enlarging the toolbox for atropochiral amine derivatives.

The first regiospecific catalytic intermolecular assembly of 2,2-disubstituted indolines has been developed. This protocol is based on a ligand and directing group free, iron-catalyzed radical [3 + 2] process, allowing efficient coupling of different N-sulfonylanilines with various α-substituted styrenes. Preliminary mechanistic studies elucidated the radical mechanism involving a reactive and versatile anilino radical and the importance of iron complex as a Lewis acid, rendering both the reactivity and regiospecificity of this transformation.