Cp*Ir(iii) and Cp*Rh(iii)-catalyzed annulation of salicylaldehydes with fluorinated vinyl tosylates

A mild, selective and redox-neutral Cp*Ir(iii)- and Cp*Rh(iii)-catalyzed C-H activation/annulation of salicylaldehydes with fluorovinyl tosylates is reported. The use of monofluorovinyl tosylate favors the synthesis of C2- and C3-substitution-free chromones via C-H activation/beta-F elimination/annulation, whereas difluorovinyl tosylate leads to the construction of C2-fluoroalkoxy chromones. Mild reaction conditions and good functional-group tolerance were observed. Further functionalization of the resulting chromones via halogenation, alkynylation, alkylation and hydrocyanation was successfully realized.

Automated summary

A mild, selective, and redox-neutral C-H activation/annulation reaction of salicylaldehydes with fluorovinyl tosylates is reported. The use of monofluorovinyl tosylate leads to the synthesis of C2- and C3-substitution-free chromones, while difluorovinyl tosylate results in the construction of C2-fluoroalkoxy chromones. The reaction exhibits mild conditions and good functional-group tolerance.