Highly Efficient Selective Benzylation of Carbohydrates Catalyzed by Iron(III) with Silver Oxide and Bromide Anion as Co‐catalysts

A highly efficient, green, and regioselective method for the benzylation of diols and polyols was developed. With the use of Ag2O (0.6 equiv.) and tetrabutylammonium bromide (0.1 equiv.) as co-catalysts, the iron(III)-catalyzed benzylation reaction proceeded to completion at 40 degrees C within 2-3h and gave the products in high yields with high regioselectivities. A mechanism involving the principle of enhanced basicity of Ag2O by soft anions was proposed.