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

摘要

Suzuki-Miyaura cross-coupling reactions of 2,2-difluoro-1-(f-butyldimethyl)sil-ylethenyl tosylate with arylboronic acids in the presence of Pd2(dba)3(10 mol ),SPhos(20 mol),and Cs2CO3(1.7 equiv)in Dioxane/H2O(10/1)at 100 ℃ for 6-9 h afforded the corresponding 1-aryl-2,2-difluoroethenyl(f-but-yldimethyl)silanes in 61-84 yields.This method is a nice tool for the direct introduction of 2,2-difluoro-1-(f-butyldimethyl)silylethenyl substituent onto an aromatic ring system from the easily accessible 2,2-difluoro-1-(f-butyldimethyl)silylethenyl tosylate.Addition-elimination reactions of 1-phenyl-2,2-difluoro-ethenyl(r-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.