A new, efficient method of fluoroselenenylation of terminal, and open-chain symmetric and unsymmetric disubstituted acetylenes and cycloalkynes, gives vicinal (E)-fluoroalkenyl selenides in moderate to high yields by addition of selenenyl fluoride equivalents. These are formed in situ from xenon difluoride and diaryl, dibenzyl or primary and secondary dialkyl diselenides. Alternatively, the benzeneselenenyl fluoride equivalent is formed by treatment of more reactive phenylselenotrialkylsilanes with xenon difluoride. The regiochemistry of the addition is strongly dependent on the steric effects of substituents bonded to the acetylene.
benzeneselenenyl fluoride towards carbone-carbone triple bonds is performed by a one-pot reaction of N-phenylselenophthalimide and triethylamine tris-hydrofluoride with disubstituted alkynes ; starting from monosubstituted alkynes, the reaction proceeds further to afford vinylic diselenated compounds after hydrofluoric acid elimination. Some products of mono-addition could be transformed into vinylic or allenic fluorides
Benzeneselenenyl fluoride equivalent was generated in situ by the reaction of silver(I) fluoride with benzeneselenenyl bromide in dichloromethane under ultrasound irradiation. Treatment of internal alkynes with this reagent afforded 2-fluoro-1-alkenyl phenylselenides in moderate yields.