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Bulky diarylammonium arenesulfonates as mild and extremely active dehydrative ester condensation catalysts

2005; Elsevier BV; Volume: 62; Issue: 2-3 Linguagem: Inglês

10.1016/j.tet.2005.09.059

1464-5416

Akira Sakakura, Shoko Nakagawa, Kazuaki Ishihara,

Oxidative Organic Chemistry Reactions

More environmentally benign alternatives to current chemical processes, especially large-scale, fundamental reactions like ester condensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the ester condensation reaction of carboxylic acids with equimolar amounts of sterically demanding alcohols and acid-sensitive alcohols. Typically, the esterification reaction is performed in heptane by heating at 80 °C in the presence of 1 mol% of the catalyst without removing water. Esterification with primary alcohols proceeds without solvents even at room temperature. Furthermore, 4-(N-mesitylamino)polystyrene resin-bound pentafluorobenzenesulfonate can be recycled more than 10 times without a loss of activity.