A telechelic fluorinated diol from 1,6-diiodoperfluorohexane

The radical addition of 1-iodoperfluorohexane (1) to allyl alcohol (2-prope n-1-ol) (2) was investigated in the presence of various initiating systems (photochemically or in the presence of redox catalysts or organic initiator s), leading to C6F13CH2CHICH2OH (3) in various yields. A scale of efficienc y of the involved radical system was proposed, triphenylphosphine and AIBN yielding the best conversions of 1. Interestingly, AIBN, when added three t imes in the course of the reaction was the most suitable for an almost quan titative consumption of 1. Then, 3 was reduced to C6F13C3H6OH (4) in high y ields by tributylstannane. Such a two-step procedure was extrapolated to th e preparation of the fluorinated telechelic diol from 1,6-diiodoperfluorohe xane (5). First, the formations of both the 1-to-1 monoadduct (6) and 1-to- 2 alpha,omega -diadduct (7) were noted and discussed: optimised conditions enabled production of 7 in 81% yield with a complete conversion of 5. Then, telechelic diol HOC3H6C6F12C3H6OH (8) was synthesised selectively in 88% y ield, from the reduction of the iodine atoms of 7 by tributylstannane. H-1, F-19 and C-13 NMR spectroscopies allowed characterisation of all the inter mediates and products without ambiguity. (C) 2001 Elsevier Science B.V. All rights reserved.