Ru(II)-Catalyzed [1,4]-Sigmatropic Rearrangement and Intramolecular Concerted SNAr of Aryl and Heteroarylthio Derivatives using Quinoid Carbene

A Ru(II)-catalyzed straightforward and efficient strategy has been developed to construct O-alkylated arylnaphthyl thioether derivatives using arylthioacetates/arylalkylthioethers with diazonaphthoquinone via a [1,4]-oxa sigmatropic rearrangement. In a complementary method, heteroaryl thioacetate/heteroaryl alkylthioethers offer O-heteroaryl alkylnaphthyl thioether derivatives via an interesting concerted intramolecular SNAr-type reaction. Both of these methods proceed through the formation of Ru-based quinoid carbene and sulfur ylide, respectively. A detailed mechanistic study and DFT calculations reveal that the reaction is going via a concerted manner. Postsynthetic modifications of the synthesized compounds led to sulfur-containing polyaromatic heterocycles.