Sulfuration of unreactive C–H bonds

The sulfuration of unreactive carbon–hydrogen bonds stands as one of the significant breakthroughs in organic synthetic chemistry in recent years. This methodology enables the efficient construction of C–S bonds through direct activation of high bond energy C–H bonds, substantially enhancing both synthetic efficiency and atom economy for sulfur-containing compounds. This review systematically summarizes the strategic progress in unreactive C–H bond sulfuration, encompassing core methodologies such as transition-metal catalysis, photocatalytic systems, and electrocatalytic systems. It analyses the sulfur source activation mechanisms under different catalytic modes, the kinetic and thermodynamic driving forces for C–H bond cleavage, and the regulatory principles of site selectivity. Furthermore, it compiles application examples in late-stage sulfuration modification of complex molecules, construction of chiral sulfur centres, and synthesis of bioactive molecules within this field.