Journal of the American Chemical Society, Vol.118, No.18, 4284-4290, 1996
Stereospecific and Regiospecific Syntheses of Alpha-Substituted and Beta-Substituted Vinyl and Dienyl Triflones via the Stille Reaction
Acetylenic anions undergo efficient sulfonylation with trifluoromethanesulfonic anhydride to provide acetylenic triflones. These materials are stereospecifically converted to (Z)-beta-iodovinyl triflones in one step via the addition of hydrogen iodide. Access to (Z)-alpha-iodovinyl triflones is also possible via a two-step process involving tributyltin hydride addition to the acetylenic triflones to generate (2)-alpha-(tributylstannyl)vinyl triflones followed by an iododestannylation reaction. Both classes of iodovinyl triflones smoothly undergo palladium (0)-mediated Stille reactions with vinyl, aryl, heteroaryl, and acetylenic stannanes to stereospecifically provide trisubstituted vinyl and dienyl triflones.
Keywords:ALKYNYL TRIFLUOROMETHYL SULFONES;ORGANIC-SYNTHESIS;COUPLING REACTIONS;PROPIOLIC ACID;TIN REAGENTS;PALLADIUM;DERIVATIVES