(Radio)Fluoro-iodination of Alkenes Enabled by a Hydrogen Bonding Donor Solvent.

We have developed a widely applicable (radio)fluoro-iodination of alkenes using readily available and easily handled KF (18F). The reactions exhibited high functional group tolerance and needed only an ambient atmosphere. Furthermore, the resulting product could be further functionalized with various nucleophiles.

Preparation of [18F]Alkenyl Fluorides Using No-Carrier-Added [18F]AgF via Silver-Mediated Direct Radiofluorination of Alkynes.

We have developed a versatile method for the radiosynthesis of [18F]alkenyl fluorides using no-carrier-added [18F]AgF via the silver-mediated direct radiofluorination of alkynes. A variety of electron-deficient internal alkynes were compatible with this strategy and gave the desired product in good regioselectivity and RCY. This method could also be applied to the late-stage radiofluorination and showed potential in nuclear medicine development.

Synthesis of ArCF2X and [18F]Ar-CF3 via Cleavage of the Trifluoromethylsulfonyl Group.

A versatile synthesis of ArCF2X and [18F]Ar-CF3 type compounds from readily available ArCF2SO2CF3 has been developed. Diverse nucleophiles, including weak nucleophiles such as halides (18F-, Cl-, Br-, and I-), RSH, and ROH, could react with ArCF2SO2CF3 efficiently to give the corresponding difluoromethylene products. The control experiments and the Hammett plot indicated that the reaction might proceed through a difluorocarbocation intermediate generated from the steric hindrance-assisted cleavage of the trifluoromethylsulfonyl group.