STEREOSPECIFIC AND REGIOSPECIFIC SYNTHESES OF ALPHA-SUBSTITUTED AND BETA-SUBSTITUTED VINYL AND DIENYL TRIFLONES VIA THE STILLE REACTION

Acetylenic anions undergo efficient sulfonylation with trifluoromethan esulfonic anhydride to provide acetylenic triflones. These materials a re stereospecifically converted to (Z)-beta-iodovinyl triflones in one step via the addition of hydrogen iodide. Access to (Z)-alpha-iodovin yl triflones is also possible via a two-step process involving tributy ltin hydride addition to the acetylenic triflones to generate (2)-alph a-(tributylstannyl)vinyl triflones followed by an iododestannylation r eaction. Both classes of iodovinyl triflones smoothly undergo palladiu m (0)-mediated Stille reactions with vinyl, aryl, heteroaryl, and acet ylenic stannanes to stereospecifically provide trisubstituted vinyl an d dienyl triflones.