One-pot desilylation-Sonogashira coupling

Horstmann J, Reger S, Neumann B, Stammler H-G, Mitzel NW. One-pot desilylation-Sonogashira coupling. ZEITSCHRIFT FUER NATURFORSCHUNG SECTION B. 2017;72(7):489-495.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