# Oxidation of sugars

I know that oxidation of sugars under different conditions produces different sugar acids, aldonic, uronic, or saccharic/aldaric as the case may be (1),(2),(3). I also know that sugars can form enediols and be reduced by $$\ce{Cu^2+}$$ (basis of Fehlings and Benedict tests).

These are my questions:

1. What principle is involved in the formation of aldonic, uronic and saccharic acids? (Specifically, don't the sugars go through enediol intermediate before forming the respective sugar acids?)

2. What sugar acids are produced in the case of say Benedict test? Aldonic, uronic or saccharic? Or something else entirely?