Reactivity of a Terminal Ti(IV) Imido Complex toward Alkenes and Alkynes: Cycloaddition vs C−H Activation

Autor:	Jennifer L. Polse, Robert G. Bergman, Richard A. Andersen
Rok vydání:	1998
Předmět:	Ethylene Thermal decomposition chemistry.chemical_element General Chemistry Biochemistry Medicinal chemistry Trimethylsilylacetylene Catalysis Cycloaddition chemistry.chemical_compound Colloid and Surface Chemistry chemistry Acetylene Pyridine Organic chemistry Reactivity (chemistry) Tin
Zdroj:	Journal of the American Chemical Society. 120:13405-13414
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja981489n
Popis:	This paper describes the reactivity of the base-free titanium imido complex Cp*2TiNPh (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)CHCH) (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-C5Me4CH2CHCH)TiN(Ph)H (5).
Databáze:	OpenAIRE
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