Multidentate Lewis acids. Structure of the 1:2 complex of a bidentate titanium trichloroalkoxide with pinacolone

Article abstract of DOI:10.1021/om00161a005

Treatment of the bis(trimethylsilyl) ether of racemic (1α,2β,3α)-3-methyl-1,2-cyclohexanediol with 2 equiv of TiCl₄ yields the titanium trichloroalkoxide 2, a bidentate Lewis acid. An X-ray crystallographic study of its 1:2 complex with pinacolone has shown that the OTiCl₃ groups are equatorial and are doubly bridged by chloride, and each binds a single pinacolone to form an approximately octahedral complex. Compound 2 therefore incorporates dual acidic sites that allow two basic substrates to be bound in close proximity.