Solventless and Metal-free Regioselective Hydrofluorination of Functionalized Alkynes and Allenes: An Efficient Protocol for the Synthesis of gem-Difluorides.

The combination of two easily handled, highly acidic liquid HF complex reagents, DMPU-12HF and KHSO4-13HF, generated a highly acidic fluorination system that facilitated exclusive Markovnikov addition of HF to widely functionalized alkynes, including alkyne tethered drugs, or allenes to produce gem-difluorides with high atom economy, and with an easy workup.