Modular synthesis of alkyl chlorides via visible light mediat-ed dual catalyzed aryl-chlorination of alkenes

Alkyl chlorides are a class of versatile building blocks widely used to generate C(sp3)-rich scaffolds through transformation such as nucle-ophilic substitution, radical addition reactions and metal-catalyzed cross-coupling processes. Despite their utility in the synthesis of high-value functional molecules, distinct methods for the preparation of alkyl chlorides are underrepresented. Here, we report a visible-light-mediated dual catalysis strategy for the modular synthesis of highly functionalized and structurally diverse β-aryl-alkyl chlorides via the coupling of diaryliodonium salts, alkenes and potassium chloride. A visible-lighted activated photocatalyst reduces a diaryliodonium salt to form an aryl radical, which adds to an alkene acceptor to create a β-aryl-alkyl radical. This radical undergoes chlorine group transfer to form the β-aryl-alkyl chloride product. A distinctive aspect of this transformation is the operation of two chlorine atom-transfer path-ways, which are dictated by the electronic properties of the open shell species arising from the substituted alkene and leveraged by the deployment of different metal group-transfer reactions. The scope of the reaction is broad in the aryl and alkene component and pro-vides access to a range of complex alkyl chlorides in good yields. Preliminary mechanistic studies identified a multifaceted role for the chloride anion in facilitating the overall transformation, which could inform the selection of appropriate group-transfer catalysts when nucleophiles other than halides are used.