36684-44-3Relevant academic research and scientific papers
Formation of RuII-alkyl-butadiene complexes from dihalogeno-RuIV-allyl precursors by the reaction with BrMg(CH2)4MgBr: a novel decomposition pathway for ruthena(IV)cyclopentane intermediates
Nagashima, Hideo,Michino, Yoshiyuki,Ara, Ken-ichi,Fukahori, Takahiko,Itoh, Kenji
, p. 189 - 196 (1991)
Treatment of (C5Me5)RuBr2(η3-CH2C(R)CH2) with BrMg(CH2)4MgBr in ether afforded the RuII-alkyl-butadiene complexes, (C5Me5)Ru(η4-C4H6)(η1-Ch2CHRCH3) .Labeling experiments have revealed a mechanism involving a double β-hydrogen elimination from ruthenacyclopentane intermediates and subsequent stepwise transfer of the hydrogen atoms to hydrogenate the η3-allyl ligand.
Competitive charge-remote and anion-induced fragmentations of the non-8-enoate anion. A charge-remote reaction which co-occurs with hydrogen scrambling
Dua, Suresh,Bowie, John H.,Cerda, Blas A.,Wesdemiotis, Chrys,Raftery, Mark J.,Kelly, Julian F.,Taylor, Mark S.,Blanksby, Stephen J.,Buntine, Mark A.
, p. 695 - 702 (2007/10/03)
The non-8-enoate anion undergoes losses of the elements of C3H6, C4H8 and C6H12 on collisional activation. The mechanisms of these processes have been elucidated by a combination of product ion and labelling (2H and 13C) studies, together with a neutralisation reionisation mass spectrometric study. These studies allow the following conclusions to be made. (i) The loss of C3H6 involves cyclisation of the enolate anion of non-8-enoic acid to yield the cyclopentyl carboxylate anion and propene. (ii) The loss of 'C4H8' is a charge-remote process (one which proceeds remote from the charged centre) which yields the pent-4-enoate anion, butadiene and dihydrogen. This process co-occurs and competes with complex H scrambling, (iii) The major loss of 'C6H12' occurs primarily by a charge-remote process yielding the acrylate anion, hexa-1,5-diene and dihydrogen, but in this case no H scrambling accompanies the process. (iv) It is argued that the major reason why the two charge-remote processes occur in preference to anion-induced losses of but-1-ene and hex-1-ene from the respective 4- and 2-anions is that although these anions are formed, they have alternative and lower energy fragmentation pathways than those involving the losses of but-1-ene and hex-1-ene; viz. the transient 4-anion undergoes facile proton transfer to yield a more stable anion, whereas the 2-(enolate) anion undergoes preferential cyclisation followed by elimination of propene [see (i) above].
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.
