The challenge associated with achieving successful conversion of cellulosic biomass to platform fuels and chemicals lies in the oxygen-rich nature of saccharides compared to the desired end products. To offset this difficulty, deoxygenation pathways had been previously explored with special attention given to the deoxydehydration (DODH) strategy, noted in Scheme 1. These efforts made use of [Re2(CO)10] and [6rRe(CO)5] as the catalyst, in conjunction with a secondary alcohol as solvent/reductant. Unfortunately, this approach has had limited success and then only with one C4 sugar (erythritol). However, the authors took note that the use of these catalysts appeared to require air and high temperature for activation, leading them to postulate that the actual active catalyst may be an oxidizedrhenium species, and that, consequently, oxorhenium compounds might represent superior catalysts for this reaction. In order to test this premise, they first studied the use of a series of oxorhenium compounds with 1,4-anhydroerythritol (1) as shown in Table 1. Based on this study, [CH3ReO3] (methyltrioxorhenium or MTO), was selected as the catalyst of choice for the deoxydehydration of a wide variety of polyols.
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