Catalytic Remote Dihalogenation of Alkenes Induced by Transposition of Esters

Organic halides play an indispensable role in functional molecule synthesis and pharmaceuticals, driving continuous efforts to develop efficient synthetic strategies. While direct alkene halogenation is an ideal route to halogenated products, conventional methods are typically limited to 1,2-dihalogenation. Here, we report a phosphordiamide-catalyzed strategy for remote dihalogenation of alkenes induced by transposition of esters. Without the need for preinstalled directing groups, this approach achieves 1,4-, 1,3-, and 2,3-dihalogenation of alkenes under mild and operationally simple conditions. Terminal/internal or cis/trans allylic/homoallylic esters undergo remote dihalogenation smoothly with good functional group tolerance. Preliminary mechanistic studies indicate that the catalyst cooperates with NBS and SOCl₂ to form an active intermediate, which enables selective remote dihalogenation promoted by ester transposition. Moreover, the products are readily accessible via gram-scale preparations, and their diverse transformations further highlight the protocol's potential as a versatile synthetic platform.