Thianthrenium Salt‐Mediated Homologative 1,3‐Dielectrophilic Activation Strategy for Alkene Difunctionalization

The chemical introduction of heteroatoms via alkene difunctionalization (e.g., dihydroxylation, diamination, dihalogenation) is a traditional route to convert abundant olefins into highly functionalized building blocks. While the transformation of unactivated alkenes to difunctionalized products bearing the newly installed heteroatom handles in 1,2‐relationship is well established, access to the corresponding 1,3‐pattern remains elusive. Herein, we disclose a thianthrenium salt–mediated homologative dielectrophilic activation method for unactivated alkenes with wide functional group tolerance. The strategy opens access to 1,3‐diazides, diamines, diols, dihalides, dithiols as well as to the full matrix of their heterodifunctionalized products from abundant olefins. At the core of our strategy is the design of a novel sulfonium atom‐transfer reagent, which undergoes selective bond cleavage to reveal a methyl thianthrenium radical, a versatile electrophilic homologative synthon which is unprecedented in synthesis.