Copper -Mediated [3+2] Oxidative Cyclization Reaction of N-Tosylhydrazones and β-Ketoesters: Synthesis of 2,3,5-Trisubstituted Furans

The first attempt at utilizing N-tosylhydrazones as two-carbon synthons has been successfully achieved, which underwent a copper-mediated [3 + 2] oxidative cyclization reaction to afford 2,3,5-trisubstituted furans in moderate to good yields. The features of this method include inexpensive metal catalyst, readily available substrates, high regioselectivity, and convenient operation. The studies provide important approaches for further exploration of the powerful and diverse reaction abilities of N-tosylhydrazones.