Metal-free oxidative lactonization of carbohydrates using molecular iodine

We describe herein the oxidative lactonization of fully or partially protected carbohydrates using molecular iodine. Oxidation of aldose hemiacetals is generally carried out by classical procedures, which are rarely chemo or regioselective. We recently reported an optimized methodology for the oxidative amidation of aldose with functionalized amines and we found molecular iodine as a good selective oxidant. This property has been already observed by other research groups but the scope of this reactivity has never been studied for carbohydrates. The main advantage of this approach relies on the operational simplicity, elimination of use of complicated reagents and procedures.