Nef Reaction (Introduction to Umpolung Chemistry)

The Nef reaction is a good way to convert nitronates into carbonyl compounds. This is a technique that can be incorporated into a strategy called "Umpolung", which refers to a reversal of polarity, such that upon converting from the nitronate to the carbonyl after some addition has occurred, structures can be afforded that would be difficult to come by when performing carbonyl chemistry. Let's look at the mechanism and some applications!