Synthesis of 4-nitrophenyl sulfones and application in the modified Julia olefination

4-Nitrophenyl (NP) sulfones were successfully employed in the modified Julia olefination reaction with carbonyl compds. The olefination reaction proceeds through a sequence of aldol addn., Smiles rearrangement, and elimination. The sulfones are easily prepd. in high yields in a two-step sequence starting from inexpensive com. available para-fluoronitrobenzenes via nucleophilic arom. substitution by a mercaptan and subsequent oxidn. under std. conditions. The modified Julia reaction between NP sulfones and a wide variety of arom. aldehydes affords the corresponding styrenes, stilbenes, and cinnamate derivs. in yields ?97% and good stereoselectivities. A mechanistic rationale is advanced to explain the obsd. results. [on SciFinder (R)]