Tetraarylethylenes from Diarylmethanones and Hexachlorodisilane: The "Sila-McMurry" Reaction.

Hexachlorodisilane reacts with diarylmethanones (aryl=C6 H5 , 4-MeC6 H4 , 4-tBuC6 H4 , 4-ClC6 H4 , 4-BrC6 H4 ) to furnish the corresponding tetraarylethylenes in good yields. The reductive conversion requires temperatures of about 160 °C and reaction times of 60-72 h. In the initial step, the Lewis-basic carbonyl groups likely generate low-valent [SiCl2 ] as an analogue of [TiCl2 ] in the classical McMurry reaction. The coupling sequence further proceeds via benzopinacolones, which have been isolated as key intermediates.