58716-61-3Relevant academic research and scientific papers
Partial Loss of Deuterium Label in Wilkinson's Catalyst Promoted Decarbonylations of Deuterioaldehydes
Baldwin, John E.,Barden, Timothy C.,Pugh, Ruth L.,Widdison, Wayne C.
, p. 3303 - 3307 (1987)
Decarbonylations of trans-2-phenylcyclopropanedeuteriocarboxaldehyde and cycloheptanedeuteriocarboxaldehyde with Wilkinson's catalyst give phenylcyclopropane and cycloheptane with partial loss of deuterium label.Loss of deuterium label is not a consequence of orthometalation of deuteriotris(triphenylphosphine)rhodium(I), a plausible reactive intermediate, for the loss is observed even when RhCl(P(C6D5)3)3 is used to effect the decarbonylation.Decarbonylations of trans-2-phenylcyclopropanecarboxaldehyde with Wilkinson's catalyst in benzene containing O-deuterioethanolafford d0 and d1 phenylcyclopropane and d0 and d1 aldehyde; neither hydrocarbon product nor recovered aldehyde is deuterium labeled when 1,1-dideuterioethanol is present in the decarbonylation reaction mixture.The hydroxyl hydrogen of ethanol associated with RhCl(P(C6H5)3)3 as normally synthesized, however, is not the hydrogen source: ethanol is not detected by 1H NMR in solutions of the catalyst, loss of deuterium label occurs even when RhCl(PPh3)3 is prepared free of possible contamination by ethanol from 2, and it is seen as well with an alternative ethanol-free decarbonylation catalyst, ClRh(dppp)2.The hydrogen source is water retained in commercial Wilkinson's catalyst.Decarbonylations of deuterioaldehyde in the presence of excess D2O give d1 product with high preservation of label.
A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: Catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations
Bagchi, Vivek,Paraskevopoulou, Patrina,Das, Purak,Chi, Lingyu,Wang, Qiuwen,Choudhury, Amitava,Mathieson, Jennifer S.,Cronin, Leroy,Pardue, Daniel B.,Cundari, Thomas R.,Mitrikas, George,Sanakis, Yiannis,Stavropoulos, Pericles
, p. 11362 - 11381 (2014/09/17)
A CuI catalyst (1), supported by a framework of strongly basic guanidinato moieties, mediates nitrene-transfer from PhI=NR sources to a wide variety of aliphatic hydrocarbons (C-H amination or amidination in the presence of nitriles) and olefins (aziridination). Product profiles are consistent with a stepwise rather than concerted C-N bond formation. Mechanistic investigations with the aid of Hammett plots, kinetic isotope effects, labeled stereochemical probes, and radical traps and clocks allow us to conclude that carboradical intermediates play a major role and are generated by hydrogen-atom abstraction from substrate C-H bonds or initial nitrene-addition to one of the olefinic carbons. Subsequent processes include solvent-caged radical recombination to afford the major amination and aziridination products but also one-electron oxidation of diffusively free carboradicals to generate amidination products due to carbocation participation. Analyses of metal- and ligand-centered events by variable temperature electrospray mass spectrometry, cyclic voltammetry, and electron paramagnetic resonance spectroscopy, coupled with computational studies, indicate that an active, but still elusive, copper-nitrene (S = 1) intermediate initially abstracts a hydrogen atom from, or adds nitrene to, C-H and C=C bonds, respectively, followed by a spin flip and radical rebound to afford intra- and intermolecular C-N containing products.
CYCLOPROPYL HALIDES. ELECTRON TRANSFER IN THE LITHIUM ALUMINIUM HYDRIDE REDUCTION OF GEM-DIBROMO AND MONOBROMOCYCLOPROPANES.
McKinney, Michael A.,Anderson, Steve W.,Keyes, Michael,Schmidt, Ronald
, p. 3443 - 3446 (2007/10/02)
The stereochemistry of reduction of mixtures of r-1-bromo-1-deuterio-c- and t-2-phenylcyclopropane and the cyclized products from 1,1-dibromo-2-(3-butenyl) cyclopropane upon reduction with lithium aluminium hydride give evidence of a configurationally equilibrated cyclopropyl radical as a reaction intermediate.
