DBU Mediated Thiocyanate and Selenocyanate Activation Enables Transition-Metal-Free Synthesis of Chalcogen-Linked Heterocycles

Abstract

We report a transition-metal-free protocol of synthesizing of chalcogen-linked organosulfur and organoselenium frameworks, via DBU mediated coupling of heteroaryl thiocyanates and selenocyanates, with alkyl halides and pseudohalides. In this transformation, heteroaryl thiocyanates and selenocyanates serve as stable and benign chalcogen sources, enabling construction of C-S and C-Se bonds under mild conditions. The reaction exhibits a broad substrate scope encompassing diverse heteroaryl scaffolds: imidazopyridines, benzothiazoles, and quinoxalines; and demonstrates excellent functional group tolerance toward both electron-donating and electron-withdrawing substituents.