A telechelic fluorinated diol from 1,6-diiodoperfluorohexane

Abstract

The radical addition of 1-iodoperfluorohexane ( 1) to allyl alcohol (2-propen-1-ol) ( 2) was investigated in the presence of various initiating systems (photochemically or in the presence of redox catalysts or organic initiators), leading to C 6F 13CH 2CHICH 2OH ( 3) in various yields. A scale of efficiency of the involved radical system was proposed, triphenylphosphine and AIBN yielding the best conversions of 1. Interestingly, AIBN, when added three times in the course of the reaction was the most suitable for an almost quantitative consumption of 1. Then, 3 was reduced to C 6F 13C 3H 6OH ( 4) in high yields by tributylstannane. Such a two-step procedure was extrapolated to the preparation of the fluorinated telechelic diol from 1,6-diiodoperfluorohexane ( 5). First, the formations of both the 1-to-1 monoadduct ( 6) and 1-to-2 α,ω-diadduct ( 7) were noted and discussed: optimised conditions enabled production of 7 in 81% yield with a complete conversion of 5. Then, telechelic diol HOC 3H 6C 6F 12C 3H 6OH ( 8) was synthesised selectively in 88% yield, from the reduction of the iodine atoms of 7 by tributylstannane. 1 H , 19 F and 13 C NMR spectroscopies allowed characterisation of all the intermediates and products without ambiguity.