The Art of Achieving Two Goals with One Strategy via Transition-Metal-Catalyzed C–H Activation

C–H functionalization is an emerging synthetic strategy allowing for innovation in total synthesis and new methodologies for drug development. One particularly useful C–H functionalization procedure has been achieved by the migratory insertion of carbenes, which are typically generated from diazo compounds.[1] Interestingly, they have been extensively explored in various C–H functionalizations, such as alkylations, alkenylations, annulations, etc.[2] However, a potential drawback of the use of diazo compounds as carbene precursors is the issue of safe handling of large quantities of these high-energy compounds.[3] Recently, our group focused on the utilization of non-diazo compounds, such as iodonium ylides have been introduced as a safe and alternative carbene coupling partner in C–H functionalizations and have grown rapidly, and a large number of synthetically challenging transformations have been disclosed.[4] In addition, we also focused on the utilization of conjugated alkynes (1,4-eneynes) in C-H functionalization reactions.[5] Overall, the iodonium ylides and conjugated alkynes brought a new diversity in synthetic transformations, such as chemo-, regioselective pathways, cascade annulations, etc. Through this talk, I will show some of our recent results, which include the diverse transformations, conditions, mechanisms and applications of the corresponding reaction in detail (Scheme 1).