Unactivated C(sp3)-H functionalization via vinyl cations

Direct functionalization of inert C(sp3)-H bonds is a topic of immense contemporary interest and exceptional value in organic synthesis. The recent research has established a novel and practical protocol which features the engagement of vinyl cation species to functionalize C(sp3)-H bonds. The discussion of the topic is arranged by the strategies to generate the reactive intermediates, including ionization of vinyl triflates, addition of electrophiles to alkynes, tandem cyclization of enynes or diynes, and decomposition of β-hydroxy-α-diazo ketones. This review closes with a personal perspective on the dynamic research area of unactivated C(sp3)-H functionalization via vinyl cations. Hopefully, it will provide timely illumination and beneficial guidance for organic chemists who are interested in this area, meanwhile, continued development of the field is strongly anticipated in the future.