Oxygen- and carbon-bound ruthenium enolates: migratory insertion, reductive elimination, .beta.-hydrogen elimination, and cyclometalation reactions

1991 ◽  
Vol 10 (9) ◽  
pp. 3326-3344 ◽  
Author(s):  
John F. Hartwig ◽  
Robert G. Bergman ◽  
Richard A. Andersen
Keyword(s):  
Reductive Elimination ◽  
Hydrogen Elimination ◽  
Migratory Insertion

scholarly journals autodE: Automated Calculation of Reaction Energy Profiles – Application to Organic and Organometallic Reactions

2020 ◽  
Author(s):  
Tom Young ◽  
Joseph Silcock ◽  
Alistair Sterling ◽  
Fernanda Duarte
Keyword(s):  
Claisen Rearrangement ◽  
Reductive Elimination ◽  
Conformational Sampling ◽  
Reaction Energy ◽  
General Applicability ◽  
Organometallic Reactions ◽  
Energy Profiles ◽  
Migratory Insertion ◽  
Human Effort ◽  
Metal Catalyzed

Calculating reaction profiles to aid in mechanistic elucidation has long been the domain of the expert computational chemist. We introduce autodE, an open-source tool capable of locating transition states and minima and delivering a full reaction energy profile with minimal human effort (https://github.com/duartegroup/autodE). autodE is broadly applicable to study organic and organometallic reaction classes, including addition, substitution, elimination, migratory insertion, oxidative addition and reductive elimination; it accounts for conformational sampling of both minima and TSs, and is compatible with many electronic structure packages. The general applicability of autodE is demonstrated in complex multi-step reactions, including metal-catalyzed cobalt- and rhodium-catalyzed hydroformylation, and an Ireland-Claisen rearrangement.

scholarly journals Mechanistic Molecular Motion of Transition-Metal Mediated Beta-Hydride Transfer: Quasiclassical Trajectories Reveal Dynamically Ballistic, Dynamically Unrelaxed, Two Step, and Concerted Mechanisms

2020 ◽  
Author(s):  
Josh Wheeler ◽  
Ryan Carlsen ◽  
Daniel Ess
Keyword(s):  
Transition State ◽  
Density Functional ◽  
Hydrogen Transfer ◽  
Transition States ◽  
Surface Shape ◽  
Concerted Mechanism ◽  
Hydrogen Elimination ◽  
Migratory Insertion ◽  
One Step ◽  
Quasiclassical Trajectories

<div>The transfer of a -hydrogen from a metal-alkyl group to ethylene is a fundamental</div><div>organometallic transformation. Previously proposed mechanisms for this transformation involve either a</div><div>two-step -hydrogen elimination and migratory insertion sequence with a metal hydride intermediate</div><div>or a one-step concerted pathway. Here, we report density functional theory (DFT) quasiclassical direct</div><div>dynamics trajectories that reveal new dynamical mechanisms for the -hydrogen transfer of</div><div>[Cp*RhIII(Et)(ethylene)]</div><div>Despite the DFT energy landscape showing a two-step mechanism with a Rh-H</div><div>intermediate, quasiclassical trajectories commencing from the -hydrogen elimination transition state</div><div>revealed complete dynamical skipping of this intermediate. The skipping occurred either extremely fast</div><div>(typically <100 femtoseconds (fs)) through a dynamically ballistic mechanism or slower through a</div><div>dynamically unrelaxed mechanism. Consistent with trajectories begun at the transition state, all</div><div>trajectories initiated at the Rh-H intermediate show continuation along the reaction coordinate. All of</div><div>these trajectory outcomes are consistent with the Rh-H intermediate <1 kcal/mol stabilized relative to</div><div>the -hydrogen elimination and migratory insertion transition states. For Co, which on the energy</div><div>landscape is a one-step concerted mechanism, trajectories showed extremely fast traversing of the</div><div>transition-state zone (<50 fs), and this concerted mechanism is dynamically different than the Rh</div><div>ballistic mechanism. In contrast to Rh, for Ir, in addition to dynamically ballistic and unrelaxed</div><div>mechanisms, trajectories also stopped at the Ir-H intermediate. This is consistent with an Ir-H</div><div>intermediate that is stabilized by ~3 kcal/mol relative to the -hydrogen elimination and migratory</div><div>insertion transition states. Overall, comparison of Rh to Co and Ir provides understanding of the</div><div>relationship between the energy surface shape and resulting dynamical mechanisms of an</div><div>organometallic transformation.</div>

Access to Substituted Indenol Ethers via a Regioselective Intermolecular Carbopalladation Cascade

2019 ◽  
Author(s):  
Brandon L. Coles-Taylor ◽  
Maximilian S. McCallum ◽  
Andrés G. Muñoz ◽  
Brian Michel
Keyword(s):  
Heck Reaction ◽  
Reductive Elimination ◽  
Catalytic Cycle ◽  
Reaction Conditions ◽  
Powerful Approach ◽  
Migratory Insertion ◽  
Ynol Ethers ◽  
Hydride Elimination ◽  
Turn Over

Alkyne carbopalladation reactions represent a powerful approach to generating multiple new C–C bonds and substituted alkenes, however regioselectivity is often challenging for intermolecular variants. By utilizing ynol ethers as polarized alkynes we observe complete regiocontrol of migratory insertion with Pd–Ar species. A Heck reaction was used to turn-over the catalytic cycle by intercepting the vinyl-Pd adduct of carbopalladation with a pendant alkene. When using <i>o</i>-iodo styrenes substrates the resulting products are oligosubstituted 1-indenol ethers with defined stereochemistry based on the initial alkene geometry. By blocking β-hydride elimination we demonstrated C–H and C–C reductive elimination steps for catalyst turnover. Herein we report the optimization of reaction conditions, scope, and alternative termination steps.

Divergent Carbonylation Reactivity Preferences of Nickel Complexes Containing Amido Pincer Ligands: Migratory Insertion versus Reductive Elimination

2011 ◽  
Vol 31 (2) ◽  
pp. 700-708 ◽  
Author(s):  
Lan-Chang Liang ◽  
Yu-Ting Hung ◽  
Yu-Lun Huang ◽  
Pin-Shu Chien ◽  
Pei-Ying Lee ◽  
...  
Keyword(s):  
Nickel Complexes ◽  
Reductive Elimination ◽  
Pincer Ligands ◽  
Migratory Insertion

Palladium-Catalyzed Annulation via Acyl C–H Bond Activation

Synlett ◽  
2018 ◽  
Vol 29 (16) ◽  
pp. 2087-2092 ◽  
Author(s):  
Gui Chen ◽  
Xueliang Huang ◽  
Yinghua Yu
Keyword(s):  
Bond Activation ◽  
Reductive Elimination ◽  
Straightforward Manner ◽  
Migratory Insertion ◽  
Palladium Catalyzed

Palladium-catalyzed annulation of ortho-bromobenzaldehydes with aryl diazoesters is achieved via a sequence of palladium carbene migratory insertion, acyl C–H bond activation and reductive elimination of a seven-membered palladacyclic intermediate. A variety of isocoumarin derivatives were furnished in a straightforward manner.

β-Hydrogen Elimination and Reductive Elimination from a κ3-PPC Nickel Complex

2018 ◽  
Vol 37 (14) ◽  
pp. 2305-2318 ◽  
Author(s):  
Amanda C. Zimmerman ◽  
Michael D. Fryzuk
Keyword(s):  
Nickel Complex ◽  
Reductive Elimination ◽  
Hydrogen Elimination

scholarly journals autodE: Automated Calculation of Reaction Energy Profiles – Application to Organic and Organometallic Reactions

2020 ◽  
Author(s):  
Tom Young ◽  
Joseph Silcock ◽  
Alistair Sterling ◽  
Fernanda Duarte
Keyword(s):  
Claisen Rearrangement ◽  
Reductive Elimination ◽  
Conformational Sampling ◽  
Reaction Energy ◽  
General Applicability ◽  
Organometallic Reactions ◽  
Energy Profiles ◽  
Migratory Insertion ◽  
Human Effort ◽  
Metal Catalyzed

Calculating reaction profiles to aid in mechanistic elucidation has long been the domain of the expert computational chemist. We introduce autodE, an open-source tool capable of locating transition states and minima and delivering a full reaction energy profile with minimal human effort (https://github.com/duartegroup/autodE). autodE is broadly applicable to study organic and organometallic reaction classes, including addition, substitution, elimination, migratory insertion, oxidative addition and reductive elimination; it accounts for conformational sampling of both minima and TSs, and is compatible with many electronic structure packages. The general applicability of autodE is demonstrated in complex multi-step reactions, including metal-catalyzed cobalt- and rhodium-catalyzed hydroformylation, and an Ireland-Claisen rearrangement.

scholarly journals Mechanistic Molecular Motion of Transition-Metal Mediated Beta-Hydride Transfer: Quasiclassical Trajectories Reveal Dynamically Ballistic, Dynamically Unrelaxed, Two Step, and Concerted Mechanisms

2020 ◽  
Author(s):  
Josh Wheeler ◽  
Ryan Carlsen ◽  
Daniel Ess
Keyword(s):  
Transition State ◽  
Density Functional ◽  
Hydrogen Transfer ◽  
Transition States ◽  
Surface Shape ◽  
Concerted Mechanism ◽  
Hydrogen Elimination ◽  
Migratory Insertion ◽  
One Step ◽  
Quasiclassical Trajectories

<div>The transfer of a -hydrogen from a metal-alkyl group to ethylene is a fundamental</div><div>organometallic transformation. Previously proposed mechanisms for this transformation involve either a</div><div>two-step -hydrogen elimination and migratory insertion sequence with a metal hydride intermediate</div><div>or a one-step concerted pathway. Here, we report density functional theory (DFT) quasiclassical direct</div><div>dynamics trajectories that reveal new dynamical mechanisms for the -hydrogen transfer of</div><div>[Cp*RhIII(Et)(ethylene)]</div><div>Despite the DFT energy landscape showing a two-step mechanism with a Rh-H</div><div>intermediate, quasiclassical trajectories commencing from the -hydrogen elimination transition state</div><div>revealed complete dynamical skipping of this intermediate. The skipping occurred either extremely fast</div><div>(typically <100 femtoseconds (fs)) through a dynamically ballistic mechanism or slower through a</div><div>dynamically unrelaxed mechanism. Consistent with trajectories begun at the transition state, all</div><div>trajectories initiated at the Rh-H intermediate show continuation along the reaction coordinate. All of</div><div>these trajectory outcomes are consistent with the Rh-H intermediate <1 kcal/mol stabilized relative to</div><div>the -hydrogen elimination and migratory insertion transition states. For Co, which on the energy</div><div>landscape is a one-step concerted mechanism, trajectories showed extremely fast traversing of the</div><div>transition-state zone (<50 fs), and this concerted mechanism is dynamically different than the Rh</div><div>ballistic mechanism. In contrast to Rh, for Ir, in addition to dynamically ballistic and unrelaxed</div><div>mechanisms, trajectories also stopped at the Ir-H intermediate. This is consistent with an Ir-H</div><div>intermediate that is stabilized by ~3 kcal/mol relative to the -hydrogen elimination and migratory</div><div>insertion transition states. Overall, comparison of Rh to Co and Ir provides understanding of the</div><div>relationship between the energy surface shape and resulting dynamical mechanisms of an</div><div>organometallic transformation.</div>

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