Fructose is a key intermediate in the conversion of cellulosic biomass to biofuels and renewable platform chemicals. Biomass-derived glucose can be isomerized to fructose using either Lewis acid or Brønsted base catalysts. Lewis acids are typically preferred as alkaline conditions promote a large number of side reactions. It is widely admitted that only low fructose yields, below 10%, are achievable with inorganic bases. Here, fructose was synthesized with 32% yield using commercially available organic amines. Glucose conversion and fructose selectivity were comparable to Lewis acids, which opens new perspectives for the base-catalyzed pathway.