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.
Phenylselenofluorination of Alkenes and Alkynes Promoted by Difluoroiodotoluene and Diphenyldiselenide
作者:Marco Tingoli、Barbara Panunzi、Andrea Picardi
DOI:10.1055/s-2004-832827
日期:——
The oxidation of diphenyldiselenide with 4-iodotoluene difluoride (DFIT) in dichloromethane produces in situ an efficient phenylselenofluorinating agent of alkenes and internal alkynes.
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.