Coupling of 2-Substituted 1-Fluorovinylstannanes with Organic Halides Catalyzed by Palladium(0)/Copper(I) Iodide. A Mild and Stereospecific Method to Monofluoroolefins

The palladium-catalyzed cross-coupling reactions of (E)- or (Z)-1-fluorovinylstannanes with aryl iodides and vinyl iodides provide good yields of stereoisomerically pure substituted fluoroolefins with retention of the double bond geometry. The reaction takes place with copper(I) iodide present as a cocatalyst at ambient temperature or in refluxing tetrahydrofuran and is tolerant of a variety of functional groups. Highly functionalized and stereoisomerically pure monofluorovinyl ketones also were obtained under mild conditions by the coupling of 1-fluorovinylstannanes with acid chlorides. 1H-{19F} NOE NMR experiments unequivocally established the stereochemistry of the coupling products E-14 and Z-14.