Efficient route to 1-aryl-2,2-difluoroethenyl(t-butyldimethyl)silanes via cross-coupling reaction of 2,2-difluoro-1-(t-butyldimethyl)silylethenyl tosylate with arylboronic acids

Suzuki-Miyaura cross-coupling reactions of 2,2-difluoro-1-(t-butyldimethyl)silylethenyl tosylate with arylboronic acids in the presence of Pd-2(dba)(3) (10 mol%), SPhos (20 mol%), and Cs2CO3 (1.7 equiv) in Dioxane/H2O (10/1) at 100 degrees C for 6-9 h afforded the corresponding 1-aryl-2,2-difluoroethenyl(t-butyldimethyl)silanes in 61%-84% yields. This method is a nice tool for the direct introduction of 2,2-difluoro-1-(t-butyldimethyl)silylethenyl substituent onto an aromatic ring system from the easily accessible 2,2-difluoro-1-(t-butyldimethyl)silylethenyl tosylate. Addition-elimination reactions of 1-phenyl-2,2-difluoro- ethenyl(t-butyldimethyl)silane with alkyllithium reagents such as n-butyllithium and i-propyllithuim provided highly (Z)-stereoselective 1-(t-butyldimethyl)silyl-2-fluoro-1-phenyl-1-alkenes in good yields.