Synthesis of fluorinated hemiketals from the reaction between alcohols and hexafluoroacetone

The alcohols, phenoxyethanol (a) and (2-hydroxymethyl)tetrahydrofuran (c) were treated with hexafluoroacetone (HFA) to give the corresponding hemiketals 2-(2′-phenoxyethoxy)-1,1,1,3,3,3-hexafluoropropan-2-ol (b) and 2-(2′-tetrahydro-pyranylmethoxy)-1,1,1,3,3,3-hexafluoropropan-2-ol (d), respectively. Also, the protected nucleosides 2′,3′-O-isopropylideneuridine (e) and 3,3′-N,O-dibenzoyl-thymidine (g) were treated with HFA to give the corresponding hemiketals 5′-O-(1-trifluoromethyl-1-hydroxytrifluoroethyl)-2′,3′-O-isopropylidene-uridine (f), and 5′-O-(1-trifluoromethyl-1-hydroxytrifluoroethyl)-3,3′-N,O-dibenzoyl-thymidine (h), respectively.