Scheme 1: Dehydration of pentose sugars for the synthesis of chiral building-blocks We hypothesised that this was due to the relatively poor solubility of picolinic acid (and the corresponding ammonium salt) in TAME. We therefore decided to explore other reaction solvents which might circumvent these problems. Esters were identified as potentially suitable, as they are typically greener and more sustainable solvents than ethers or aromatic hydrocarbons, and offer a better safety profile (i.e they are typically not prone to peroxide formation). They are also considerably more polar so should be much more effective at solubilising polar substrates and/or ammonium salts derived from them. Importantly, we had previously observed that stoichiometric amidation mediated by B(OCH2CF3)3 could be carried out in ethyl acetate as a solvent without any significant amidation of the ester being observed. 3e To date, there is only a single report of a catalytic amidation reaction performed in an ester solvent, using BuB(OH)2 as a catalyst in n-propyl acetate. Aside from this, esters have not been explored as solvents for catalytic amidation reactions.