Barbier–Wieland degradation
The Barbier–Wieland degradation is a procedure for shortening the carbon chain of a carboxylic acid by one carbon. It only works when the carbon adjacent to the carboxyl is a simple methylene bridge. The reaction sequence involves conversion of the carboxyl and alpha carbon into an alkene, which is then cleaved by oxidation to convert the former alpha position into a carboxyl itself.
