Fluorination of (+)-chiro-inositol with SF4/HF to give 2α,3β-difluoro-7-oxabicyclo[2.2.1]heptane-5α,6α-sulfite

The fluorination of (+)-chiro-inositol with SF4/HF under moderate conditions affords a single product studied by 1H and 19F and 13C NMR spectroscopy. These have been fully assigned with the aid of other physical techniques and compared with a computer-generated model. This data indicate the product to be 2α,3β-difluoro-7-oxabicyclo[2.2.1]heptane-5α,6α-sulfite 3 which was subsequently confirmed by single-crystal X-ray analysis. A mechanism for the reaction is proposed and is compared with that proposed for the formation of the product obtained from the fluorination of myo-inositol.