Decelerating Effect of Alkenes in the Oxidative Addition of Phenyl Iodide to Palladium(0) Complexes in Heck Reactions

2002 ◽  
Vol 21 (21) ◽  
pp. 4540-4545 ◽  
Author(s):  
Christian Amatore ◽  
Emmanuelle Carré, ◽  
Anny Jutand ◽  
Youcef Medjour
Keyword(s):  
Oxidative Addition ◽  
Heck Reactions

Mechanistic pathways for oxidative addition of aryl iodides to the low-ligated diethanolamine palladium(0) complex in phosphine-free Heck reactions

2009 ◽  
Vol 694 (24) ◽  
pp. 3852-3858 ◽  
Author(s):  
Zorica D. Petrović ◽  
Vladimir P. Petrović ◽  
Dušica Simijonović ◽  
Svetlana Marković
Keyword(s):  
Oxidative Addition ◽  
Heck Reactions ◽  
Aryl Iodides

Reactivity of Pd(0)(NHC)2 (NHC: N-Heterocyclic Carbene) in Oxidative ­Addition with Aryl Halides in Heck Reactions

Synlett ◽  
2006 ◽  
Vol 2006 (18) ◽  
pp. 3088-3094 ◽  
Author(s):  
Anny Jutand ◽  
Sylvain Roland ◽  
Pierre Mangeney
Keyword(s):  
Oxidative Addition ◽  
Aryl Halides ◽  
Heck Reactions

Mechanism of the oxidative addition of aryl halides to bis-carbene palladium(0) complexes

2010 ◽  
Vol 82 (7) ◽  
pp. 1393-1402 ◽  
Author(s):  
Anny Jutand ◽  
Julien Pytkowicz ◽  
Sylvain Roland ◽  
Pierre Mangeney
Keyword(s):  
Electrochemical Reduction ◽  
Chemical Reduction ◽  
Oxidative Addition ◽  
Heterocyclic Carbenes ◽  
Electrochemical Technique ◽  
Mixed Complex ◽  
Heck Reactions ◽  
Dissociative Mechanism ◽  
Aryl Bromides

Bis-N-heterocyclic carbenes Pd0 complexes, Pd0(NHC)2, are efficient catalysts in Heck reactions performed with aryl bromides or chlorides. The Pd0(NHC)2 that are not stable are generated in situ from PdII precursors PdY2(NHC)2 (Y = halides) after a chemical reduction. The latter procedure can be mimicked by an electrochemical reduction. The transient Pd0(NHCBn)2 is generated by electrochemical reduction of PdY2(NHCBn)2, and its reactivity in oxidative addition to aryl bromides and chlorides is characterized by the same electrochemical technique with the determination of the rate constants. Pd0(NHCBn)2 is found to be more reactive than the mixed complex Pd0(NHCBn)(PPh3). Both are the reactive species in an associative mechanism. Comparison with the isolated Pd0(NHCtBu)2 reveals that Pd0(NHCBn)2 is more reactive than Pd0(NHCtBu)2 even if the latter reacts via the mono-carbene Pd0(NHCtBu) in a dissociative mechanism. This suggests that the formation of mono-carbene Pd0(NHC) is not a guarantee for a fast oxidative addition because it is always generated at low concentration in its equilibrium with the related nonreactive bis-carbene Pd0(NHC)2.

Some Problems in the Oxidative Addition and Binding of an Ethylene to a Transition Metal Center.

1987 ◽  
Vol 6 (4) ◽  
pp. 902-902
Author(s):  
Jerome Silestre ◽  
Maria Calhorda ◽  
Roald Hoffman ◽  
Page Stoutland ◽  
Robert Bergman
Keyword(s):  
Transition Metal ◽  
Oxidative Addition ◽  
Metal Center

Reversible Oxidative-Addition and Reductive-Elimination of Thiophene from a Titanium Complex and Its Thermally-Induced Hydrodesulfurization Chemistry

2019 ◽  
Author(s):  
Alejandra Gomez-Torres ◽  
J. Rolando Aguilar-Calderón ◽  
Carlos Saucedo ◽  
Aldo Jordan ◽  
Alejandro J. Metta-Magaña ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Ring Opening ◽  
Thiophene Ring ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Thermally Induced ◽  
Titanium Complex

<p>The masked Ti(II) synthon (<sup>Ket</sup>guan)(<i>η</i><sup>6</sup>-Im<sup>Dipp</sup>N)Ti (<b>1</b>) oxidatively adds across thiophene to give ring-opened (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti[<i>κ</i><sup>2</sup>-<i>S</i>(CH)<sub>3</sub><i>C</i>H] (<b>2</b>). Complex <b>2</b> is photosensitive, and upon exposure to light, reductively eliminates thiophene to regenerate <b>1</b> – a rare example of early-metal mediated oxidative-addition/reductive-elimination chemistry. DFT calculations indicate strong titanium π-backdonation to the thiophene π*-orbitals leads to the observed thiophene ring opening across titanium, while a proposed photoinduced LMCT promotes the reverse thiophene elimination from <b>2</b>. Finally, pressurizing solutions of <b>2 </b>with H<sub>2</sub> (150 psi) at 80 °C leads to the hydrodesulfurization of thiophene to give the Ti(IV) sulfide (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti(S) (<b>3</b>) and butane. </p>

Ni(0)-Catalyzed α-Allylic Alkylation of Regular Ketones with 1,3-Dienes under pH and Redox-neutral Conditions

2019 ◽  
Author(s):  
Tiantian Chen ◽  
Yang Yang ◽  
Liyu Xie ◽  
Haijian Yang ◽  
Guangbin Dong ◽  
...  
Keyword(s):  
Oxidative Addition ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Dual Role ◽  
Allylic Alkylation ◽  
Cross Coupling Reaction ◽  
Neutral Conditions

<p>We report a Ni(0)-catalyzed cross coupling reaction between simple ketones and 1,3-dienes. A variety of a-allylic alkylation products were formed in an 1,2-addition manner with excellent regioselectivity. Water was found to significantly accelerate this transformation. A HO-Ni-H species generated from oxidative addition of Ni(0) to H<sub>2</sub>O is proposed to play a “dual role” in activating both the ketone and the diene substrate.</p>

On the Reactivity of mRNA Caps: C-H Oxidative Addition of 7-Methylguanosine to Pt(0)

2019 ◽  
Author(s):  
Maria Ines Leitao ◽  
Carmen Gonzalez ◽  
Zuzanna Filipiak ◽  
Ana Petronilho
Keyword(s):  
Oxidative Addition ◽  
Carbene Complex ◽  
Proton Loss

<p>7-methylguanosine, the so-called mRNA cap 0 bears a very labile C8-H bond, due to the formation of an ylide/N-heterocyclic carbene, upon proton loss. The reaction of 7-methylguanosine with Pt(PPh3)4, via C-H oxidative addition, yields a hydrido–PtII carbene complex and this reactivity can be extrapolated to 7,9-dimethylguanine. </p>

Nickel and Cobalt-Catalyzed Coupling of Alkyl Halides with Alkenes via Heck Reactions and Radical Conjugate Addition

2013 ◽  
Vol 13 (6) ◽  
pp. 802-813 ◽  
Author(s):  
Qun Qian ◽  
Zhenhua Zang ◽  
Yang Chen ◽  
Weiqi Tong ◽  
Hegui Gong
Keyword(s):  
Conjugate Addition ◽  
Alkyl Halides ◽  
Heck Reactions

Hydrogen-halide versus alkyl-halide oxidative addition in dimethyl platinum(II) complexes: Crystal structure of [PtBr2(bpy)]

2007 ◽  
Vol 360 (8) ◽  
pp. 2661-2668 ◽  
Author(s):  
Badri Z. Momeni ◽  
Saeideh Hamzeh ◽  
Simin S. Hosseini ◽  
Frank Rominger
Keyword(s):  
Crystal Structure ◽  
Alkyl Halide ◽  
Oxidative Addition ◽  
Hydrogen Halide
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