UNPRECEDENTED MCMURRY REACTIONS WITH ACYLSILANES - ENEDISILANE FORMATION VERSUS BROOK REARRANGEMENT

The first inter- and intramolecular McMurry reactions of aroyltrimethy lsilanes to substituted 1,2-bis(trimethylsilyl)ethene derivatives 2a-c and 7 are described. A low-valent titanium reagent prepared by the re duction of TiCl3 with Na on inorganic supports (Al2O3, NaCl, TiO2) tur ned out to be best suited. Depending on the reaction conditions and on the particular substitution patterns of the substrates, Brook rearran gements of the intermediate 1,2-disilylated titanium-1,2-diolates lead ing to the formation of C,O-disilyl-enol ethers may compete with the M cMurry deoxygenation pathway.