Copper-Catalyzed Synthesis of Quinoline-4-thiols from Diaryliodonium Salts, Alkynyl Sulfides, and Nitriles

A three-component cascade cyclization catalyzed by copperwas employedto synthesize quinoline-4-thiols using easily available diaryliodoniumsalts, alkynyl sulfides, and nitriles as starting materials. Sulfuratoms play an important role in controlling the regioselectivity,by stabilizing the high-valent vinyl copper intermediate. Meanwhile,the sulfide group at position 4 of quinoline could be further utilizedas a transformable group for ipso-transformationand as a directing group for C-H functionalization, affordingvarious multifunctional quinoline derivatives.

Automated summary

A three-component cascade cyclization catalyzed by copper was used to synthesize quinoline-4-thiols using easily available diaryliodonium salts, alkynyl sulfides, and nitriles as starting materials. Sulfur atoms play a crucial role in controlling regioselectivity by stabilizing the high-valent vinyl copper intermediate. Additionally, the sulfide group at position 4 of quinoline can be further utilized as a transformable group for ipso-transformation and as a directing group for C-H functionalization, leading to the synthesis of various multifunctional quinoline derivatives.