A redox-neutral bimetallic Rh(iii)/Ag(i) relay catalysis allowed the efficient construction of 3-alkylidene isoindolinones and 3-alkylidene isobenzofuranones. The Rh(iii) catalyst was responsible for the C-H monofluoroalkenylation reaction, whereas the Ag(i) salt was an activator for the follow-up cyclization. The methodology developed was applied as a key step in the rapid total synthesis of the natural product aristolactam BII.