MnI/AgI Relay Catalysis: Traceless Diazo‐Assisted C(sp2)–H/C(sp3)–H Coupling to β‐(Hetero)Aryl/Alkenyl Ketones

: An unprecedented MnI /AgI -relay-catalyzed C(sp2 )-H/C(sp3 )-H coupling of (vinyl)arenes with α-diazoketones is reported, wherein the diazo group was exploited as a traceless auxiliary for control of regioselectivity. Challenging β-(hetero)aryl/alkenyl ketones were obtained through this operationally simple approach. The cascade process merges denitrogenation, carbene rearrangement, C-H activation, and hydroarylation/hydroalkenylation. The robustness of this method was demonstrated at preparative scale and applied to late-stage diversification of natural products.