Difluorination of Furonaphthoquinones

An unprecedented difluorination reaction was developed based on the furonaphthoquinone skeleton of natural products tanshinones and their analogues. By using Selectfluor as the fluorinating source and H₂O as the hydroxyl source, a wide range of unique polycyclic α,α-difluoro β,β-dihydroxyl para-quinone products were achieved with yields up to 90%. The mechanistic studies revealed that the reaction might undergo tandem multiple electrophilic and nucleophilic substitutions, as well as cleavages of C-O and C-C bonds. This approach not only provides a new method to synthesis of α,α-difluoro ketones, but also affords a series of unique chemotypes for biological activity screening.