PUB - Publikationen an der Universität Bielefeld

Coupling of diethynyldiphenylsilane (1) with aryl halides under Sonogashira conditions affords the symmetrical diarylacetylenes bis(2-methylpyridin-5-yl) acetylene (2), bis(4-fluorophenyl) acetylene (3) and bis(4-trifluoromethylphenyl) acetylene (4) in 60% to 82% yield. In the case of 2, the by-product bis(2-methylpyridin-5-yl) butadiyne (2a) was isolated in 12% yield. The occurring desilylation reaction was investigated by treating bis(phenylethynyl) diphenylsilane (5) under the same-conditions. The formation of 1-fluoro-4-(phenylethynyl) benzene (6), 1-trifluoromethyl4-( phenylethynyl) benzene (7) and (tetrafluoropyridin4- yl) ethynylbenzene (8) in 70 to 84% yield and the cleavage of hexaphenylcyclotrisiloxane were observed in all cases.