Organocobalt cluster complexes. 28. Highly stabilized (nonacarbonyltricobalt)carbon-substituted carbonium ions

Seyferth, Dietmar; Williams, Gary H.; Eschbach, C. Scott; Nestle, Mara Ozolins; Merola, Joseph S.; Hallgren, John E.

doi:10.1021/ja00511a015

Cited by 22 publications

(8 citation statements)

References 8 publications

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“…183 As expected, heating a tetrahydrofuran solution of the methyl compound (33, R = Me) with trifluoroacetic acid and triethylsilane at reflux for four hours produces the related hydrocarbon complex (35, R = Me) in 72% yield. Somewhat surprising, however, is the report that the hexafluorophosphate salt of the phenylsubstituted carbocation (34, R = Ph, X − = PF 6 − ), preformed by treatment of the corresponding alcohol with hexafluorophosphoric acid, produces only 7% of the related hydrocarbon complex when exposed to triethylsilane in tetrahydrofuran for 1.5 hours at room temperature.…”

Section: Oh Obnsupporting

confidence: 56%

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Ionic and Organometallic‐Catalyzed Organosilane Reductions

2009

Ionic and Organometallic‐Catalyzed Organosilane Reductions

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Section: Oh Obnsupporting

confidence: 56%

“…248). 183,310,425 Acyl ferrocene derivatives are reduced to the respective methylene compounds with Et 3 SiH/TFA (Eqs. 249 180 Reductive Amination.…”

Section: Chomentioning

confidence: 99%

Ionic and Organometallic‐Catalyzed Organosilane Reductions

2009

Ionic and Organometallic‐Catalyzed Organosilane Reductions

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“…Atoms that determine the plane are indicated with an asterisk. products in eq l. 13 Cryoscopic molecular weight determinations revealed that the organozinc compounds 1 and 2 are dimeric in benzene. 13 Although association degrees up to eight have been found for other organozinc complexes, the presence of bulky organo groups at the coordinating donor atoms may favor the formation of monomeric species even when this would imply three-coordination at the zinc atom.…”

Section: Resultsmentioning

confidence: 99%

“…13 The 'H and 13C NMR spectroscopic data are summarized in Tables IV and V. X-ray Data Collection, Structure Determination, and . 13 The 'H and 13C NMR spectroscopic data are summarized in Tables IV and V. X-ray Data Collection, Structure Determination, and .…”

Section: Reaction Of the A-amino Ketones And A-hydroxy Iminesmentioning

confidence: 99%

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Reactivity of 1-aza-4-oxo-1,3-butadienes (.alpha.-imino ketones) toward diorganozinc reagents: regio- and chemoselective transfer of organo groups in the ZnR2/R1N:C(R2)C(R3):O system and x-ray structure of [cyclic] [EtZn(Et)(tert-Bu)NC(H):C(Me)O]2

Koten¹,

Vliet²,

Buysingh³

et al. 1987

Organometallics

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The 1:1 reaction of ZnRz with a-imino ketones [R1N=C(R2)C(R3)=O] leads to quantitative formation of dinuclear [RZn(R)(R1)NC(R2)=C(R3)0I2 (1) (for R = primary and secondary alkyls) and [RZn(R')-N=C(R2)C(R3,R)OI2 (2) (for R = aryl, methyl, and tertiary alkyl). An X-ray structure determination of [EtZn(Et)(t-Bu)NC(H)=C(Me)O]2 (la) has established the dinuclear structure that consists of a N,Ochelate coordinated [Et(t-Bu)NC(H)=C(Me)O]-monoanionic ligand and a central four-membered Zn202 ring formed by intermolecular Zn-0 coordination. The Zn atoms are tetrahedrally surrounded by two 0 atoms, one N atom, and one C atom. Crystals of la are triclinic, space group P1, with cell constants a = 7.57 (1) A, b = 8.82 (2) A, c = 11.14 (1) A, (Y = 102.6 ( 1 ) O , / 3 = 91.8 (l)', y = 114.4 ( 2 ) O , and 2 = 1.The structure was refined to a final R of 0.089 with 1051 reflections. Product formation in the Znh/cu-imino ketone system depends on the nature of the R group that migrates from Zn to the NCCO skeleton. Different radical activity of R (for R = Et, i-Pr, t-Bu, and Bz) as generated in the 1:l complex, with the ligand bonded in the N,O-chelate coordination mode (see A in Scheme 11), is the predominant factor for the discrimination between imino N-addition (for R' = Et, LPr, and Bz; 20%) and carbonyl C-addition (R' = t-Bu and Bz; 80%). For R = Me and p-tolyl alternative routes involving a N-monodentate coordination mode and/or heterolytic activation may also account for the exclusive formation of carbonyl C-addition products. I I 8 . (1) (a) University of Amsterdam. (b) University of Utrecht. (2) (a) Mauze, B.; Miginiac, M. Bull. SOC. Chim. and references therein. (b) van Koten, G.; Jastrzebski, J. T. B. H.; Vrieze, K. J. Organomet. Chem. 1983, 250, 49 and references therein. (5) (a) Klerks, J. M.; Jastrzebski, J. T. B. H.; van Koten, G.; Vrieze, K. J. Organomet. Chem. 1982,224,107. (b) Klerks, J. M.; Stufkens, D. J.; van Koten, G.; Vrieze K. J. Organomet. Chem. 1979, 181, 271. (c) Jastrzebski, J. T. B. H.; van Koten, G.; Vrieze, K., unpublished results.An interesting aspect of the R-DAB/ZnR2 system is the detailed mechanistic information that could be obtained through the isolation and characterization of (dia-and paramagnetic) organozinc intermediates from these reac-Pattison, J.; Wade, K. J. Chem. SOC. A 1968, 57. (9) (a) Alcaide, B.; Lopes-Mardomingo, C.; Perez-Oeeorio, R.; Plumet, J. The formal addition of the Pt-H bond of the cationic complex [trans-Pt(H)(PEtJ2(acetone)]+ across the C-C triple bonds of alkynyl ligands affords cationic dinuclear complexes containing bridging alkenylidene ligands. The synthesis and characterization of eight such complexes are reported.On the basis of structural data for a member complex, these molecules are believed to possess Pt-Pt, Pt-Fe, Pt-Au, Pt-W, Pt-Ni, or Pt-Pd bonds. Diagnostic spectroscopic characterization data are provided. Furthermore, a similar addition of a Pt-Me bond across an acetylide ligand also affords a dinuclear p-alkenylidene complex.

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Ionic and Organometallic‐Catalyzed Organosilane Reductions

Larson

Fry²

2008

Organic Reactions

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This chapter presents a critical review of synthetically useful variations of ionic methods for hydrogenation of organic compounds. In practice ionic hydrogenation involves the formal introduction of hydride from a donor source to an electron‐deficient carbon center. In this chapter, organosilicon hydrides are used as the source of ionic hydride with the goal of completing and updating earlier review work. Organosilicon compounds with at least one Si‐H bond have the ability to serve as mild‐air and water‐stable sources of hydrides and, thus, have reducing properties. In general, organosilicon hydrides do not undergo spontaneous reactions with organic compounds unless the organic substrate is a reasonably strong electrophile or the silane is first activated by the interaction of a nucleophilic species with a nucleophilic center. The organosilicon hydrides are covalent compounds that have little or no nucleophilic properties on their own. The use of these hydrides often provides a means of effecting reductions of organic substrates under very mild conditions and with excellent functional group selectivity. Consideration of the nature of the Si‐H bonds provides insight into the chemical behavior of these hydrides. Enhanced hydridic nature manifests itself in the chemical behavior of hydrosilanes.

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Organocobalt cluster complexes. 28. Highly stabilized (nonacarbonyltricobalt)carbon-substituted carbonium ions

Cited by 22 publications

References 8 publications

Ionic and Organometallic‐Catalyzed Organosilane Reductions

Ionic and Organometallic‐Catalyzed Organosilane Reductions

Reactivity of 1-aza-4-oxo-1,3-butadienes (.alpha.-imino ketones) toward diorganozinc reagents: regio- and chemoselective transfer of organo groups in the ZnR2/R1N:C(R2)C(R3):O system and x-ray structure of [cyclic] [EtZn(Et)(tert-Bu)NC(H):C(Me)O]2

Ionic and Organometallic‐Catalyzed Organosilane Reductions

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