High-yield synthesis of fluorinated benzothiazolyl sulfones: general synthons for fluoro-julia olefinations.

[reaction: see text] General, high-yield tandem electrophilic fluorination and modified Julia olefination for the synthesis of fluoro olefins is reported. A series of alpha-fluoro 1,3-benzothiazol-2-yl sulfone-based synthons were synthesized via deprotonation-fluorination. Of critical importance for high-yield fluorinations were heterogeneous reaction conditions, as under homogeneous conditions only starting sulfones were recovered. The alpha-fluoro 1,3-benzothiazol-2-yl sulfones so obtained were subjected to condensations with a variety of aldehydes and ketones to afford high yields of regiospecifically fluorinated olefins.