934199-95-8Relevant academic research and scientific papers
Alkene Insertions into a Ru-PR2 Bond
Burton, Krista M. E.,Pantazis, Dimitrios A.,Belli, Roman G.,McDonald, Robert,Rosenberg, Lisa
supporting information, p. 3970 - 3980 (2016/12/22)
An unusually broad series of discrete alkene insertion reactions has provided the opportunity to examine the mechanism(s) of this fundamental carbon-heteroatom bond-forming process. Ethylene, electron-rich and electron-poor (activated) alkenes all react with the Ru-P double bond in Ru(η5-indenyl)(PCy2)(PPh3) to form κ2-ruthenaphosphacyclobutanes. Thermal decomposition of these metallacycles in solution, via alkene deinsertion and β-hydride elimination, is particularly favored for electron-rich alkenes, and hydride-containing decomposition products are implicit intermediates in the observed isomerization of 1-hexene. Kinetic studies, including a Hammett analysis of the insertion reactions of para-substituted styrenes, suggest that two distinct inner-sphere pathways operate for the insertion of electron-rich versus activated alkenes. DFT analyses have identified one pathway involving simple cycloaddition via a four-centered transition state and another that proceeds through an η2-alkene intermediate. Such an intermediate was observed spectroscopically during formation of the ethylene metallacycle, but not for substituted alkenes. We propose that “pre-polarized”, activated alkenes participate in direct cycloaddition, while rate-determining η2-adduct formation is necessary for the activation of electron-rich alkenes toward migratory insertion into the Ru-P bond.
Concerted [2+2] cycloaddition of alkenes to a ruthenium-phosphorus double bond
Derrah, Eric J.,Pantazis, Dimitrios A.,McDonald, Robert,Rosenberg, Lisa
, p. 3367 - 3370 (2010/07/15)
(Figure Presented) A square deal for Ru=PR2: The Ru=PR 2 π bond in a terminal phosphido complex undergoes regio- and stereoselective [2+2] cycloaddition reactions of alkenes to yield metallaphosphacyclobutanes (see structure; P red, Ru yellow, C gray), which are analogous to olefin metathesis intermediates.
A highly reactive ruthenium phosphide complex exhibiting Ru-P π-bonding
Derrah, Eric J.,Pantazis, Dimitrios A.,McDonald, Robert,Rosenberg, Lisa
, p. 1473 - 1482 (2008/10/09)
Multiple bonding in the terminal phosphido complex [Ru(PCy 2)(η5-indenyl)(PPh3)J (2a) is clearly demonstrated by solution, solid-state, and computational studies. Reactions of this dark blue, half-sandwich complex with CO, MeI, HNEt3Cl, HCl, NH4PF6, H2, and Et3SiH demonstrate an unusual range of behavior resulting from combined coordinative unsaturation at Ru, high nucleophilicity/basicity of the phosphido P, and π-character of the Ru-P interaction. The terminal, π-bound phosphido structure is general for a range of PR2 species (R = Pri (2b), Ph (2c), Tolp (2d)). The very reactive diarylphosphido analogues 2c,d have been observed spectroscopically at low temperatures and can be trapped quantitatively as their CO adducts, [Ru(PAr2)(η5- indenyl)(CO)(PPh3)] (3c,d), in which the Ru-P bond order is reduced to 1. Complex 2a and its analogue [Ru(PPri2) (η5-indenyl)(PPh3)] (2b) are consistently isolated with ～15% of their structural isomers, the ruthenium hydrido phosphaalkenes 9a,b, resulting from an apparent 1,2-H shift.
