Mechanistic Exploration of the Transmetalation and Reductive Elimination Events Involving PdIV -Abnormal NHC Complexes in Suzuki-Miyaura Coupling Reactions: A DFT Study

2018 ◽  
Vol 24 (23) ◽  
pp. 6155-6168 ◽  
Author(s):  
Totan Mondal ◽  
Sriman De ◽  
Sayan Dutta ◽  
Debasis Koley
Keyword(s):  
Reductive Elimination ◽  
Dft Study ◽  
Coupling Reactions

Carbon-Heteroatom Cross-Coupling via an Electronically Excited Nickel (II) Complex

2019 ◽  
Author(s):  
Randolph Escobar ◽  
Jeffrey Johannes
Keyword(s):  
Energy Transfer ◽  
Functional Groups ◽  
Cross Coupling ◽  
Reductive Elimination ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
General Methodology ◽  
Cross Coupling Reactions ◽  
Electronically Excited ◽  
Energy Transfer Pathway

<div>While carbon-heteroatom cross coupling reactions have been extensively studied, many methods are specific and</div><div>limited to a set of substrates or functional groups. Reported here is a method that allows for C-O, C-N and C-S cross coupling reactions under one general methodology. We propose that an energy transfer pathway, in which an iridium photosensitizer produces an excited nickel (II) complex, is responsible for the key reductive elimination step that couples aryl halides to 1° and 2° alcohols, anilines, thiophenols, carbamates and sulfonamides.</div>

Ni(COD)(DMFU): A Heteroleptic 16-Electron Precatalyst for 1,2-Diarylation of Alkenes

Synlett ◽  
2021 ◽  
Author(s):  
Nana Kim ◽  
Van T. Tran ◽  
Omar Apolinar ◽  
Steven Wisniewski ◽  
Martin Eastgate ◽  
...  
Keyword(s):  
Nickel Complex ◽  
Active Catalyst ◽  
Cross Coupling ◽  
Reductive Elimination ◽  
Coupling Reactions ◽  
Beneficial Effects ◽  
Cross Coupling Reactions ◽  
Growing Body ◽  
Hydride Elimination

Electron-deficient olefin (EDO) ligands are known to promote a variety of nickel-catalyzed cross-coupling reactions, presumably by accelerating the reductive elimination step and preventing undesired β-hydride elimination. While there is a growing body of experimental and computational evidence elucidating the beneficial effects of EDO ligands, significant gaps remain in our understanding of the underlying coordination chemistry of the Ni–EDO species involved. In particular, most procedures rely on in situ assembly of the active catalyst, and there is a paucity of pre-ligated Ni-EDO precatalysts. Herein, we investigate the 16-electron, heteroleptic nickel complex, Ni(COD)(DMFU), and examine the performance of this complex as a precatalyst in 1,2-diarylation of alkenes.

scholarly journals Carbon(sp3)-nitrogen bond-forming reductive elimination from phosphine-ligated alkylpalladium(II) amide complexes: A DFT study

Tetrahedron ◽  
2019 ◽  
Vol 75 (2) ◽  
pp. 137-143 ◽  
Author(s):  
Quan Jiang ◽  
D. Matthew Peacock ◽  
John F. Hartwig ◽  
Thomas R. Cundari
Keyword(s):  
Reductive Elimination ◽  
Dft Study ◽  
Bond Forming ◽  
Nitrogen Bond

scholarly journals DFT Study of Unstrained Ketone C-C Bond Activation via Rhodium(I)-Catalyzed Suzuki-Miyaura Cross-Coupling Reactions

2019 ◽  
Author(s):  
Dengmengfei Xiao ◽  
Lili Zhao ◽  
Diego Andrada
Keyword(s):  
Density Functional ◽  
Bond Activation ◽  
Chemical Reactivity ◽  
Cross Coupling ◽  
Underlying Mechanism ◽  
Reductive Elimination ◽  
Coupling Reactions ◽  
Co Catalysts ◽  
Cross Coupling Reactions ◽  
Strain Model

Unstrained cyclic ketones can participate in cooperative Suzuki-Miyaura cross-coupling type reaction using rhodium(I)-based catalyst via C-C bond activation. The regioselectivity indicates a trend where the most substituted side is activated and it is controlled by the beta-substituents. In this work, Density Functional Theory (DFT) calculations have been carried out to disclose the underlying mechanism in the reaction of a ketone series and arylboronate using ylidene as ancillary ligand and pyridine as co-catalysts. The computed energies suggest the reductive elimination step with the highest energy while the reductive elimination has the highest energy barrier. By the means of the Activation Strain Model (ASM) of chemical reactivity, it is found that the ketone strain energy released on the oxidative addition does not control the relativity of the OA reactivity, but indeed is the interaction energy between Rh(I) and C-C bond the ruling effect. The effect of the beta-substituents on regioselectivity has been additionally studied.

Selectivity in carbon–carbon coupling reactions at palladium(IV) and platinum(IV)

2019 ◽  
Vol 97 (7) ◽  
pp. 529-537 ◽  
Author(s):  
Richard J. Puddephatt
Keyword(s):  
Activation Energy ◽  
Transition State ◽  
Computational Study ◽  
Bond Formation ◽  
Reductive Elimination ◽  
Organometallic Complexes ◽  
Axial Position ◽  
Coupling Reactions ◽  
Methyl Group ◽  
Trigonal Bipyramidal

The isomerization and reductive elimination reactions from octahedral organometallic complexes of palladium(IV) and platinum(IV) usually occur through five-coordinate intermediates that cannot be directly detected. This paper reports a computational study of five-coordinate complexes of formulae [PtMe3(bipy)]+, [PtMe2Ph(bipy)]+, and [PtMe(CH2CMe2C6H4)(bipy)]+ (M = Pd or Pt, bipy = 2,2′-bipyridine), particularly with respect to reactivity and selectivity in reductive elimination. All of the complexes are predicted to have square pyramidal structures with the bipy and two R groups in the equatorial positions and one R group in the axial position, and axial–equatorial exchange occurs by a pairwise mechanism, with the transition state having a pinched trigonal bipyramidal (PTBP) stereochemistry, with one nitrogen and two R groups in the trigonal plane. The activation energy for isomerization is lower than that for reductive elimination in all cases. For the complexes [MMe2Ph(bipy)]+, the activation energies for reductive elimination with Me–Me or Me–Ph coupling are similar. For the complexes [MMe(CH2CMe2C6H4)(bipy)]+, the reductive elimination with Me–C6H4 bond formation from the isomer with the methyl group in the axial position is predicted and is attributed to it having the best conformation of the Me and C6H4 groups for C–C bond formation. In all cases, the selectivity for reductive elimination is similar for M = Pd or Pt, but reactivity is higher for M = Pd. The relevance of this work to selectivity in catalysis is discussed.

scholarly journals Differences between the elimination of early and late transition metals: DFT mechanistic insights into the titanium-catalyzed synthesis of pyrroles from alkynes and diazenes

2017 ◽  
Vol 8 (3) ◽  
pp. 2413-2425 ◽  
Author(s):  
Jiandong Guo ◽  
Xi Deng ◽  
Chunyu Song ◽  
Yu Lu ◽  
Shuanglin Qu ◽  
...  
Keyword(s):  
Transition Metals ◽  
Bond Formation ◽  
Reductive Elimination ◽  
Dft Study ◽  
Late Transition Metals ◽  
Late Transition ◽  
Elimination Pathway ◽  
Back Donation

A DFT study demonstrates that titanium is capable of promoting C–N bond formation via an unconventional reductive elimination pathway featuring back-donation (REBD).

Which one is faster? A kinetic investigation of Pd and Ni catalyzed Negishi-type oxidative coupling reactions

2015 ◽  
Vol 44 (46) ◽  
pp. 19777-19781 ◽  
Author(s):  
Jie Xin ◽  
Guanghui Zhang ◽  
Yi Deng ◽  
Heng Zhang ◽  
Aiwen Lei
Keyword(s):  
Oxidative Coupling ◽  
Reductive Elimination ◽  
Kinetic Investigation ◽  
Coupling Reactions ◽  
Rate Determining Step ◽  
The Difference ◽  
Oxidative Coupling Reactions

The difference between Pd and Ni has been investigated based on the Negishi-type oxidative coupling reactions in which reductive elimination was proved to be the rate determining step.

C−C Reductive Elimination in Palladium Complexes, and the Role of Coupling Additives. A DFT Study Supported by Experiment

2009 ◽  
Vol 131 (10) ◽  
pp. 3650-3657 ◽  
Author(s):  
Martín Pérez-Rodríguez ◽  
Ataualpa A. C. Braga ◽  
Max Garcia-Melchor ◽  
Mónica H. Pérez-Temprano ◽  
Juan A. Casares ◽  
...  
Keyword(s):  
Reductive Elimination ◽  
Palladium Complexes ◽  
Dft Study
Sign in / Sign up

Export Citation Format

Share Document