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

摘要

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.