The disclosure provides the use of aryl or heteroaryl boronic acid in the preparation of 5-(hydroxymethyl)fufural (HMF) from saccharides. The aryl or heteroaryl boronic bearing electron-withdrawing groups on the aryl or heteroaryl ring of the boronic acid provided good yields. The disclosure provides a method for preparing HMF from saccharides in the presence of aryl or heteroaryl boronic acid. The disclosure provides a method for converting a saccharide other than fructose in fructose via a dehydrogenation reaction catalyzed by aryl or heteroaryl boronic acid.