On the nature of organoindium intermediates: the formation of readily isolable difluoropropargylindium reagents and their regioselectivity towards electrophilic substitutions

The structure and reactivity of intermediate propargylindium complexes have been investigated. Their reaction with electrophiles produced a difluoroalkyne or -allene, depending on the nature of the electrophiles. A mechanism based on the Curtin-Hammett principle was invoked to explain this phenomenon. A newly proposed mechanism on the formation of indium(III) complexes, through the intermediacy of indium(I) species, could help to explain the reaction of indium with 1,1,1-difluorobromo-2-alkynes in the presence of aldehydes.