Stereospecific Synthesis of ( Z )‐ α ‐Fluoro‐ β ‐trifluoromethyl Vinyl Iodides and Their Application to the Synthesis of Polyfluorinated Thienyl Alkadienes †

The direct iodination of polyfluorinated vinyl stannanes by tin‐iodine exchange methodology was achieved giving( Z )‐ α ‐fluoro‐ β ‐trifluoromethyl vinyl iodides stereospecifically. Changing the substituent in R group from the electron‐withdrawing group to electron‐donating group led to an increase in the yield from 78% to 90%, while it was moved from para to meta position the reaction did not afford a dramatic change in the yield (90% to 95%). In addition, this reaction also can be applied to the vinyl stannane with heterocyclic group. The further coupling reaction of prepared vinyl iodide containing heterocyclic moiety with ( Z )‐ α ‐fluoro‐ β ‐trifluoromethylstannanes gave polyfluorinated heterocyclic alkadienes with 2 E ,4 E ‐selectivity.