Reactivity of fully methylated η(3):η(4)-allyldiene(η(5)-cyclopentadienyl)-titanium(II) towards alkynylketones. The crystal structure of an unexpected 1:2 adduct
2003
Abstract
Fully methylated η3:η4-allyldiene(η5-cyclopentadienyl)titanium(II) (1) reacts with alkynylketones RC÷CC(O)Me (R = SiMe3 (3a) and ferrocenyl (3b)) to give the expected product of the C=O group insertion into one Ti-CH2 bond 4a and 4b, respectively. Compound 4a could not be isolated in pure form due to its high solubility; a minor product of two-fold addition (5) was isolated instead.
Complex 5, formally [1 + 23a], was characterized as monocyclopentadienyl bis(alkoxy)organyl complex, where the alkoxyorganyl ligand arise from C=O insertion into one Ti-CH2 and the Ti-C(cyclopentadienyl) bonds. The structures of compounds 4b and 5 were determined by single-crystal X-ray diffraction. (÷ means tripple bond)