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.