Efficient, Scalable Synthesis of Functionalized Pyrrolo[2,1-f][1,2,4]triazines

An efficient, scalable synthesis of functionalized 5-fluoropyrrolo[2,1-f][1,2,4]triazines was developed from readily available starting materials. The synthesis is highlighted by a safe, Cu mediated difluoroacetate addition to vinyl TMS, selective formylation of a 3-fluoropyrrole, and sequential imine formation followed by cyclization to the triazine core. Addition of other electrophiles to 3-fluoropyrrole was also shown to be equally selective.