Reactions involving hexafluoropropylene oxide: novel ring opening reactions and resolution of a racemic mixture of a bromofluoro ester, ultrasound mediated Reformatsky reactions and stereoselectivity

Abstract

A novel ring opening reaction of hexafluoropropylene oxide (HFPO) 1 with lithium bromide/zinc bromide and subsequent reaction of the resulting acyl fluoride with primary and secondary alcohols gave bromofluoro esters 2, 3, 4 and 7. Reaction of the corresponding acyl fluoride with water leads to acid 9 which on treatment with dehydroabietylamine 10 gave the diastereomeric salt 11. Resolution of 11 and subsequent hydrolysis and esterification reactions led to enantiomerically pure ester 12. Reformatsky reactions with 2 were studied which gave the alcohols 6 and 5. A Reformatsky reaction of 12 with formaldehyde afforded an alcohol 13 which is indicated by NMR spectroscopy in the presence of a chemical shift reagent to have proceeded stereoselectively.