An Approach to 1,3,4-Oxadiazolidines via N,N′-Diborylated Hydrazine

We report a novel simple metal-free synthetic strategy that enables efficient access to highly substituted 1,3,4-oxadiazolidines that have remained synthetically elusive through conventional approaches from N,N'-diborylated hydrazines and aldehydes. This method also facilitates a one-pot protocol, wherein N,N'-diborylated hydrazine is generated in situ from azobenzene, 4,4'-bipyridine, and bis(pinacolato)diboron, followed by its reaction with aldehydes. The resulting 1,3,4-oxadiazolidines exhibit potential anti-inflammatory properties. Mechanistic insights, supported by DFT calculations, suggest a concerted aldehyde nitroboration-condensation cascade pathway for this transformation.