Synthetic pathways leading to 5-deoxy-5,5,5-trifluoropentofuranoses are reported. The main difficulty was to obtain a good diastereoselectivity at the C-4 carbon bearing the CF3group. For the ribose and the lyxose derivatives the problem was partially solved by reacting trifluoromethyltrimethylsilane with 1,4-lactones of suitable glyconic acids leading to hemiketalic 1-deoxy-1,1,1-trifluoro-2-ketoses. Reduction of these ketoses with NaBH4or LiA1H4allowed the desired configuration at the C-4 carbon. For the arabinose and the xylose derivatives it was found more convenient to synthesize uncyclised 1-deoxy-1,1,1-trifluoro-2-ketopentoses by Dess-Martin oxidation of the corresponding protected alcohols. Highly selective reductions of these trifluoromethylketones led toarabinoorxyloderivatives depending on the reducing agent.