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

Abstract

Suzuki–Miyaura cross‐coupling reactions of 2,2‐difluoro‐1‐(t‐butyldimethyl)silylethenyl 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 °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.