Nickel-Catalyzed Alkyne Cyclotrimerization Assisted by a Hemilabile Acceptor Ligand: A Computational Study

Orsino, Alessio F.; Moret, Marc‐Etienne

doi:10.1021/acs.organomet.0c00172

Cited by 14 publications

(12 citation statements)

References 87 publications

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“…All calculations were performed with Gaussian 09 . The functional M06-L, suitable for applications in transition metal chemistry, has been successfully used in numerous studies on transition metal-catalyzed organic reactions. − It was combined with the dispersion correction D3 in this work to enhance computational accuracy. Structures were optimized and characterized by frequency calculations to be energy minima (zero imaginary frequencies) or transition states (only one imaginary frequency) at the M06-L-D3/6-31G(d,p) level with the solvent (toluene) effects included using the SMD solvation model.…”

Section: Methodsmentioning

confidence: 99%

Mechanistic Insights into Formation of All-Carbon Quaternary Centers via Scandium-Catalyzed C–H Alkylation of Imidazoles with 1,1-Disubstituted Alkenes

et al. 2021

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This density functional theory (DFT) study reveals a detailed plausible mechanism for the Sc-catalyzed C–H cycloaddition of imidazoles to 1,1-disubstituted alkenes to form all-carbon quaternary stereocenters. The Sc complex binds the imidazole substrate to enable deprotonative C2–H bond activation by the Sc-bound α-carbon to afford the active species. This complex undergoes intramolecular cyclization (CC into Sc–imidazolyl insertion) with exo-selectivity, generating a β-all-carbon-substituted quaternary center in the polycyclic imidazole derivative. The Sc-bound α-carbon deprotonates the imidazole C2–H bond to deliver the product and regenerate the active catalyst, which is the rate-determining step. Calculations illuminate the electronic effect of the ancillary Cp ligand on the catalyst activity and reveal the steric bias caused by using a chiral catalyst that induce the enantioselectivity. The insights can have implications for advancing rare-earth metal-catalyzed C–H functionalization of imidazoles.

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Section: Methodsmentioning

confidence: 99%

Mechanistic Insights into Formation of All-Carbon Quaternary Centers via Scandium-Catalyzed C–H Alkylation of Imidazoles with 1,1-Disubstituted Alkenes

et al. 2021

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“…A computational study of the mechanism for acetylene trimerization was conducted with truncated versions of 42 and 43 (Ph instead of p-tol phosphine substituents). 182 The role of ligand coordination mode is most notable for two steps in the catalytic mechanism (Scheme 25): oxidative cyclization (P → Q) and the addition of the third alkyne equivalent (Q → R).…”

Section: Suzuki (C−c) and Buchwald−hartwig (C−n) Couplingmentioning

confidence: 99%

Structurally-Responsive Ligands for High-Performance Catalysts

Blacquiere

2021

ACS Catal.

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Hemilabile ligands that undergo reversible changes in denticity have long been exploited to enable catalyst activation and to increase lifetime. However, this common description does not fully reflect reality with respect to the diversity of known ligand types, modes of action, and impacts on catalysis. The term structurally responsive ligand (SRL) is employed here to encompass ligands that exhibit selftuning denticity, hapticity, or versatile coordination. This Perspective covers case study examples of SRLs in catalysis and their influence on catalyst lifetime, rate, and selectivity. The examples include leading and emerging catalysts for enabling transformations, which emphasizes both the breadth and significance of this class of ligands.

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“…[2c] Recently, a paper from Orsino and Moret about the "Nickelcatalyzed alkyne cyclotrimerization assisted by a hemilabile acceptor ligand: A computational study", was published. [3] In the past we studied such reactions for the catalytic tri-and tetramerization of alkynes by nickel-catalysts and found highly productive systems, which were published several years ago. [4,5,6,7] These papers show in detail the background for this and how the systems were step by step [4,5] developed to extremely productive homogeneous catalysts.…”

Section: Introductionmentioning

confidence: 99%

Influence of Impurities on the Productivity in Homogeneous Catalytic Reactions: Trimerization of 1,4‐Dimethoxy‐but‐2‐yne and Tetramerization of Propargyl Alcohol

Rosenthal

2021

Zeitschrift anorg allge chemie

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The productivity of homogeneous catalytic reactions is often described by the yield. This is misleading, and also the TON (turnover number) as well as the TOF (turnover frequency) which better describe it, give no objective informations. These data strongly depend on the substrate to catalyst ratio and also on impurities in the substrate which poison the effective catalyst and reduce the described yield as well as the turnover numbers and the turnover frequencies. In this concept a model is presented, how by changing the amounts of catalyst and the substrate it is possible with several restrictions to calculate the possible maximum for the TON. For the example of trimerization of 1,4-dimethoxy-but-2-yne to hexakis-methoxymethylbenzene and for tetramerization of propargyl alcohol to 1,3,5,7and 1,3,6,8-hydroxymethyl-1,3,5,7-cyclooctatetraene by previous purification of the substrate or by certain additives as scavengers the access to these compounds is described in detail. By using both methods, extremely high turnover numbers a million were realized.

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Nickel-Catalyzed Alkyne Cyclotrimerization Assisted by a Hemilabile Acceptor Ligand: A Computational Study

Cited by 14 publications

References 87 publications

Mechanistic Insights into Formation of All-Carbon Quaternary Centers via Scandium-Catalyzed C–H Alkylation of Imidazoles with 1,1-Disubstituted Alkenes

Mechanistic Insights into Formation of All-Carbon Quaternary Centers via Scandium-Catalyzed C–H Alkylation of Imidazoles with 1,1-Disubstituted Alkenes

Structurally-Responsive Ligands for High-Performance Catalysts

Influence of Impurities on the Productivity in Homogeneous Catalytic Reactions: Trimerization of 1,4‐Dimethoxy‐but‐2‐yne and Tetramerization of Propargyl Alcohol

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