A Novel Stereospecific Route to (<i>E</i>)- and (<i>Z</i>)-(2-Substituted-1,2-difluoroethenyl)stannanes

Abstract

In the presence of 1.2−1.5 equiv of potassium fluoride, a variety of (E)- and (Z)-(2-substituted-1,2-difluoroethenyl)silanes reacted with tributyltin chloride in DMF at room temperature to 80 °C to afford the corresponding stannanes in good yields with overall retention of configuration. These stannanes are useful intermediates for the introduction of the (E)- and (Z)-1,2-difluoroethylene unit into organic molecules. Under similar reaction conditions, only catalytic potassium fluoride (5−10%) was needed for these conversions when tributyltin chloride was replaced by tributyltin oxide. The mechanism and scope of this transformation is discussed.