A New Synthetic Route to (Trifluoromethyl)quinolines: Nickel-Catalyzed Insertion of an Alkyne into an Aromatic C–S Bond by Formation of a Thianickelacycle and Thermal Desulfidation

Abstract

AbstractWe have developed a nickel-catalyzed insertion reaction of an alkyne into a 2-(trifluoromethyl)-1,3-benzothiazole to give a seven-membered benzothiazepine that is converted into a 2-(trifluoromethyl)quinoline by thermal desulfidation. This process can be considered a formal substitution of a sulfur atom with an alkyne. The structure of the thianickelacycle intermediate formed through oxidative addition of a C–S bond in the benzothiazole to nickel(0) was confirmed by X-ray single-crystal structure analysis and in situ X-ray absorption fine-structure spectroscopy.