e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Gem-difluorination of aminoalkynes via highly reactive dicationic species in superacid HF-SbF5: application to the efficient synthesis of difluorinated cinchona alkaloid …
A variety of alkynylated amines, amides, and imides are reacted in the superacid system HF- SbF5 to give regioselectively new β-gem-difluoroamines. The reaction, which is not observed in pure HF, is consistent with the formation of a dicationic intermediate (ie, both vinylic and adjacent protonated N-ammonium cations). Application to the regioselective and efficient synthesis of difluorinated cinchona alkaloid derivatives is described.
