Synthesis of 3,4-Bis(hydroxymethyl)-2,2,5,5-tetraethylpyrrolidin-1-oxyl via 1,3-Dipolar Cycloaddition of Azomethine Ylide to Activated Alkene

A simple method for the synthesis
of sterically shielded pyrrolidine
nitroxides, including the title compound, has been suggested. The
key procedure implies assembling the pyrrolidine ring from α-amino
acid, ketone, and activated alkene in a three-component domino process,
followed by oxidation to nitrone and Grignard reagent addition. The
new nitroxides demonstrate very high stability against reduction with
ascorbate.