REACTIVITY OF TITANOCENEVINYLIDENE WITH ENOLIZABLE KETONES CP-ASTERISK-TI-2(CH=CH2)(OC(=CH2)C6H11), AN ENOLATE WITH AN UNUSUALLY OBTUSE TI-O-C ANGLE

A variety of enolizable ketones reacts with the titanocenevinylidene intermediate [Cp*Ti-2=C=CH2,] 2, which is formed in situ by thermolysis of Cp*2TiC(=CH2)CH2CH2 1, to yield under regio- and stereoselective control vinyltitanium enolates 7 in excellent yields. Therefore the formation of Delta(1)- and of E-configurated enolates is preferred. A single-crystal diffraction study of Cp*Ti-2(CH=CH2)(OC(=CH2)C6H11) 74 shows a typical O-bonded monomeric enolate with a short Ti-O distance of 1.859(2) Angstrom and a Ti-O-C angle of 165.9(2)degrees. The complexes 7 do not exhibit typical enolate reactivity, especially 74 does not react with neither methyl iodide nor benzaldehyde.