Coupling of 2-Substituted 1-Fluorovinylstannanes with OrganicHalides Catalyzed by Palladium(0)/Copper(I) Iodide. A Mild andStereospecific Method to Monofluoroolefins
The palladium-catalyzed cross-coupling reactions of (E)- or (Z)-1-fluorovinylstannanes with aryliodides and vinyl iodides provide good yields of stereoisomerically pure substituted fluoroolefinswith retention of the double bond geometry. The reaction takes place with copper(I) iodide presentas a cocatalyst at ambient temperature or in refluxing tetrahydrofuran and is tolerant of a varietyof functional groups. Highly functionalized and stereoisomerically pure monofluorovinyl ketonesalso were obtained under mild conditions by the coupling of 1-fluorovinylstannanes with acidchlorides. 1H-{19F} NOE NMR experiments unequivocally established the stereochemistry of thecoupling products E-14 and Z-14.