Alkynyl Sulfide: An Unexplored yet Versatile Alkynyl Species for Chemoselective Cross-Electrophile Coupling

The development of robust and readily available carbon electrophiles for cross-electrophile coupling (XEC) is important and highly desirable. Herein, we report a cobalt-catalyzed highly chemoselective XEC between alkynyl sulfides and various alkyl halides, which tolerates otherwise widely employed coupling handles such as a series of aromatic (pseudo)halogens (Ar-I/Br/Cl/OTf/OTs/SMe) and provides an easy and efficient method for synthesizing internal alkynes (>60 examples achieving up to 96% yields). Mechanistic studies have revealed that the leaving sulfide anion of alkynyl sulfides adjusts the reactivity of alkynyl-Co intermediates, enabling excellent chemoselectivity.