Direct Deoxydehydration of Cyclic Trans-Diol Substrates: An Experimental and Computational Study of the Reaction Mechanism of vanadium(V)-Based Catalysis

The deoxydehydration of carbohydrates represents a key target to leverage renewable biomass resources chemically. Using a vanadium(V)-based catalyst, we demonstrate that it is possible to directly deoxydehydrate trans-cyclic diol substrates. Accompanying mechanistic characterisation of this process by density functional calculations points to an energetically tractable route for deoxydehydration of cyclic trans-diol substrates involving stepwise cleavage of the diol C-O bonds via the triplet state; experimentally, this is supported by light dependence of the reaction. Calculations also indicate that cyclic cis-diols and a linear diol substrate can additionally proceed by a concerted singlet DODH mechanism. This work potentially opens a new and cost-effective way to efficiently convert carbohydrates of trans-diol stereochemistry into alkenes.