95342-06-6Relevant academic research and scientific papers
Regiospecific Hydride Abstraction from Metallacycles: Conversion of Metallacyclopentanes to Cationic ?-Allylic Complexes
Barabotti, Paolo,Diversi, Pietro,Ingrosso, Giovanni,Lucherini, Antonio,Nuti, Franca
, p. 2517 - 2524 (2007/10/02)
The rhoda- and irida-cyclopentane complexes (η5-C5Me5)(PPh3)> react with the trityl cation + to give the η3-1-methylallyl derivatives 3-CH2CHCHMe)(η5-C5Me5)(PPh3)>.Deuterium-labelling studies show that in these cases as well as in the previously reported palladacyclopentane->(η3-1-methylallyl)palladium complex transformations, the trityl cation abstracts regiospecifically one of the β-hydrogen atoms of the metallacyclic moiety.The involvement of a ?-3-butenyl intermediate which rearranges to a η3-1-methylallyl derivative is confirmed by reacting the palladium and rhodium dihalides, and 5-C5Me5)(PPh3)I2>, with 3-butenylmagnesium bromide.In the case of palladium a ?-3-butenyl complex is obtained which, by reacting with AgBF4, gives the η3-1-methylallyl derivative 3-CH2CHCHMe)(Ph2PCH2CH2PPh2)>.In the case of rhodium the PPh3 ligand is lost and the η3-1-methylallyl compound 3-CH2CHCHMe)(η5-C5Me5)I> is obtained directly.By reacting 5-C5Me5)(PPh3)I2> with 3-pentanylmagnesium bromide, the η3-1,3-dimethylallyl complex 3-MeCHCHCHMe)(η5-C5Me5)(PPh3)> is obtained.Mechanistic implications are discussed along with the significance of the reactions studied in connection with the role of transition-metal metallacyclopentane derivatives in organometallic chemistry and in catalysis.
