Construction of Difluorinated Cycloheptadienones via Substrate-Controlled Regioselective Conjugate Addition of Difluoroenoxysilanes to Tropones and Their Anticancer Activity

The substrate-controlled regioselective conjugate addition (1,8- and 1,4-addition) of tropones with difluoroenoxysilanes is reported, which offered an approach for the selective synthesis of multifunctional seven-membered 3,5-cycloheptadien-1-ones and 1,3-cycloheptadien-1-ones featuring a gem-difluoroketone moiety. Moreover, these fluorinated cyclo-heptadienones exhibit effective anti-proliferative activities (IC₅₀<1 μM) for human colon carcinoma HCT116 cells in vitro, thus providing potential lead compounds for developing new anticancer agents.