220249-40-1Relevant academic research and scientific papers
Reactivity of a terminal Ti(IV) imido complex toward alkenes and alkynes: Cycloaddition vs C-H activation
Poise, Jennifer L.,Andersen, Richard A.,Bergman, Robert G.
, p. 13405 - 13414 (1998)
This paper describes the reactivity of the base-free titanium imido complex Cp*2Ti=NPh (1) (Cp= pentamethylcyclopentadienyl) toward alkenes and alkynes. Complex 1 reacts with ethylene and acetylene to generate the azametallacycles Cp*2Ti(N(Ph)CH2CH2) (2) and Cp*2Ti(N(Ph)CH=CH) (3), respectively. In the case of ethylene, the cycloaddition is readily reversible, and 2 was characterized spectroscopically under an ethylene atmosphere. We have also examined the reactivity of 1 toward phenyl- and trimethylsilylacetylene and have found that 1 activates the alkynyl C-H bond to give anilido-acetylide complexes Cp*2Ti(N(Ph)H)C≡ CR (6, R = Ph; 7, R = SiMe3). This reaction proceeds without observable intermediate metallacyclobutene complexes such as those observed previously for the reaction of the related oxo complex Cp*2Ti(O)pyr (pyr = pyridine) with terminal alkynes. Thermolysis of azametallacyclobutene 3 results in formation of the novel ring-activated complex Cp*(η5,η1-C5Me4CH2CH=CH)TiN(Ph)H (5).
