Stereoselective Shono Oxidations: Use of Alkylidene Protective Groups

Anodic formation of N,O-acetals using amides or carbamates as starting materials, commonly referred to as Shono oxidation, has been an iconic reaction in the field of synthetic organic electrochemistry. However, it is, in principle, not stereoselective and the commonly used neighboring-carbonyl-group participation is not usually effective. Herein, we demonstrate that the use of alkylidene protective groups is extremely effective in controlling the stereo selectivity. Although the detailed mechanism remains an open question, under our reaction conditions, the conformation restriction effect is dominant rather than the steric hindrance effect.