Abstract
The reaction of 3-bromo-4-oxo-l-oxyl-2,2,6,6-tetramethylpiperidine (1) with a solid sodium, alkoxide of primary or secondary alcohol provides a short way to prepare ester of 3-carboxy-1-oxyl-2,2,5,5-tetramethylpyrrolidine where the ring contraction from six (1) to five (6a-f) in a Favorski rearrangement occurs.