Discovery and Exploration of the Efficient Acyclic Dehydration of Hexoses in DMSO/Water

Current gaps in the development of sustainable processes include lacking strategies to systematically identify and optimize the formation of new products. The dehydration of hexoses to 5-hydroxymethylfurfural (HMF) is a particularly widely studied process. In an attempt to identify a new high-selectivity conversion of glucose, quantitative NMR spectroscopy was used to screen conditions that were reported to yield high conversion of glucose, but low formation of HMF. In this manner, an olefinic six-carbon byproduct was identified. By water addition, selectivity for the compound was nearly tripled relative to previous reports. The detection of high-yielding side reactions in the formation of HMF is remarkable, considering how extensively HMF formation has been studied. High selectivity for the acyclic pathway allows hitherto unobserved intermediates in this pathway to be identified using in situ NMR spectroscopy. An additional, presumably cyclic, pathway contributes to HMF formation.