Additive-free synthesis of S-substituted isothioureas via visible-light-induced four-component reaction of α-diazoesters, aryl isothiocyanates, amines and cyclic ethers

An additive-free and environmentally friendly strategy has been realized for the construction of S-substituted isothioureas through visible-light-induced multicomponent reaction starting from α-diazoesters, aryl isothiocyanates, amines and cyclic ethers. This methodology features simple operation, mild reaction conditions, favorable functional group tolerance, easily available starting materials and high efficiency.