Syntheses of fluorous propenes from 3-perfluoroalkyl-2-iodo-1-propanols

3-(Perfluoroalkyl)-1-propenes are obtained in excellent yields up to 100-g quantities by deiodination–dehydroxylation reactions of the easily accessible 2-iodo-3-(perfluoroalkyl)-propanols with red phosphorus and catalytic amounts of iodine or with an SnCl2/POCl3 reagent pair in pyridine (fluorous Cornforth reaction). Both methods afford fluorous propenes in high GC purity, the former one has high atom-economy and proceeds safely if the fluorous iodohydrin precursors are added in increments; for the solid ones using a ‘hot-melt’ dropping funnel. The title fluorous propenes are effectively isolated by co-distillation with pyridine.