Synthesis of 4-Nitrophenyl Sulfones and Application in the Modified Julia Olefination

Abstract

4-Nitrophenyl (NP) sulfones have been successfully employed in the modified Julia olefination reaction with carbonyl compounds. The olefination reaction proceeds through a sequence of aldol addition, Smiles rearrangement, and elimination. The sulfones are easily prepared in high yields in a two-step sequence starting from inexpensive commercially available para-fluoronitrobenzenes via nucleophilic aromatic substitution by a mercaptane and subsequent oxidation under standard conditions. The modified Julia reaction between NP sulfones and a wide variety of aromatic aldehydes affords the corresponding styrenes, stilbenes and cinnamate derivatives in yields up to 97% and good stereoselectivities. A mechanistic rationale is advanced to explain the observed results.