Copper(I)-only catalyzed reactions of (E)-2,3-difluoro-3-stannylacrylic ester with acid chlorides and mechanistic studies of the 'copper effect' in Stille coupling reactions

摘要

The reactions of (E)-2,3-difluoro-3-stannylacrylic ester with acid chlorides under catalysis of CuI stereospecifically afforded ethyl (2Z)-2,3-difluoro-4-oxo-substituted 2-butenoates in good yields. Moreover, direct spectroscopic observation of the corresponding organocopper reagent was observed for the first time in Stille coupling reactions of organostannanes.