Dialkylbiaryl phosphines are a valuable class of ligand for Pd-catalyzed amination reactions and have been applied in a range of contexts. This perspective attempts to aid the reader in the selection of the best choice of reaction conditions and ligand of this class for the most commonly encountered and practically important substrate combinations.

Dialkylbiaryl phosphines in Pd-catalyzed amination: a user's guide

Many industrial catalysts contain isolated metal sites on the surface of oxide supports. While such catalysts have been used in a broad range of processes for more than 40 years, there is often a very limited understanding about the structure of the catalytically active sites. This review discusses how Surface Organometallic Chemistry (SOMC) engineers surface sites with well-defined structures and provides insight about the nature of active sites in industrial catalysts, focusing in particular on olefin production and conversion processes

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Bridging the Gap between Industrial and Well-Defined Supported Catalysts

The first highly Z- and enantioselective class of ring-opening/cross-metathesis reactions is presented. Transformations are promoted in the presence of <2 mol % of chiral stereogenic-at-Mo monoaryloxide complexes bearing an adamantylimido ligand that are prepared and used in situ. Reactions involve meso oxabicyclic substrates and afford the desired pyrans in 50-85% yield and up to >98:<2 enantiomer ratio. Importantly, the desired chiral pyrans thus obtained bear a Z olefin either exclusively (>98:<2 Z/E) or predominantly (>or=87:13 Z/E).

Highly Z- and Enantioselective Ring-Opening/Cross-Metathesis Reactions Catalyzed by Stereogenic-at-Mo Adamantylimido Complexes

Catalyst discovery is increasingly relying on computational chemistry, and many of the computational tools are currently being automated. The state of this automation and the degree to which it may...

Automated in Silico Design of Homogeneous Catalysts

United States. Army Research Office (Institute for Soldier Nanotechnologies, Contract No. DAAD-19-02-D-0002)

Z-Selective and Syndioselective Ring-Opening Metathesis Polymerization (ROMP) Initiated by MonoAryloxidePyrrolide (MAP) Catalysts

Since its early days, olefin metathesis has been in the focus of scientific discussions and technology development. While heterogeneous olefin metathesis catalysts based on supported group 6 metal oxides have been used for decades in the petrochemical industry, detailed mechanistic studies and the development of molecular organometallic chemistry have led to the development of robust and widely used homogeneous catalysts based on well-defined alkylidenes that have found applications for the synthesis of fine and bulk chemicals and are also used in the polymer industry. The development of the chemistry of high-oxidation group 5–7 alkylidenes and the use of surface organometallic chemistry (SOMC) principles unlocked the preparation of so-called well-defined supported olefin metathesis catalysts. The high activity and stability (often superior to their molecular analogues) and molecular-level characterisation of these systems, that were first reported in 2001, opened the possibility for the first direct structure–activity relationships for supported metathesis catalysts. This review describes first the history of SOMC in the field of olefin metathesis, and then focuses on what has happened since 2007, the date of our last comprehensive reviews in this field.

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Olefin metathesis: what have we learned about homogeneous and heterogeneous catalysts from surface organometallic chemistry?

High-throughput experimentation and multivariate modeling allow identification of noncovalent interactions (NCIs) in monoaryloxy-pyrrolide Mo imido alkylidene metathesis catalysts prepared in situ as a key driver for high activity in a representative metathesis reaction (homodimerization of 1-nonene). Statistical univariate and multivariate modeling categorizes catalytic data from 35 phenolic ligands into two groups, depending on the substitution in the ortho position of the phenol ligand. The catalytic activity descriptor TON1h correlates predominantly with attractive NCIs when phenols bear ortho aryl substituents and, conversely, with repulsive NCIs when the phenol has no aryl ortho substituents. Energetic span analysis is deployed to relate the observed NCI and the cycloreversion metathesis step such that aryloxide ligands with no ortho aryls mainly impact the energy of metallacyclobutane intermediates (SP/TBP isomers), whereas aryloxides with pendant ortho aryls influence the transition state energy for the cycloreversion step. While the electronic effects from the aryloxide ligands also play a role, our work outlines how NCIs may be exploited for the design of improved d0 metathesis catalysts.

Noncovalent Interactions Drive the Efficiency of Molybdenum Imido Alkylidene Catalysts for Olefin Metathesis

A combination of high-throughput experimentation (HTE), surface organometallic chemistry (SOMC) and statistical data analysis provided the platform to analyze in situ silica-grafted Mo imido alkylidene catalysts based on a library of 35 phenols. Overall, these tools allowed for the identification of σ-donor electronic effects and dispersive interactions and as key drivers in a prototypical metathesis reaction, homodimerization of 1-nonene. Univariate and multivariate correlation analysis confirmed the categorization of the catalytic data into two groups, depending on the presence of aryl groups in ortho position of the phenol ligand. The initial activity (TOFin) was predominantly correlated to the σ-donor ability of the aryloxy ligands, while the overall catalytic performance (TON1 h) was mainly dependent on attractive dispersive interactions with the used phenol ligands featuring aryl ortho substituents and, in sharp contrast, repulsive dispersive interactions with phenol free of aryl ortho substituents. This work outlines a fast and efficient workflow of gaining molecular-level insight into supported metathesis catalysts and highlights σ-donor ability and noncovalent interactions as crucial properties for designing active d0 supported metathesis catalysts.

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Molecular-level insight in supported olefin metathesis catalysts by combining surface organometallic chemistry, high throughput experimentation, and data analysis

Benchmarked Intrinsic Olefin Metathesis Activity: Mo vs. W

All primary data files that were contributed to the publication by the Buchmeiser Research Group can be found here. Data obtained by the Coperet Research Group is not included. Procedures, recation conditions and used analytical equipment is discussed in detail in the experimental section or the supporting information of the paper. NMR Spectra are named according to the numbering in the publication. 1H-NMR, 19F-NMR and 13C-NMR spectra were recorded using a Bruker Avance III 400 (400MHzfor 1H, 101MHz for 13C) spectrometer.

Silica‐Supported Cationic Tungsten Imido Alkylidene Stabilized by an N‐Heterocyclic Carbene Ligand Boosts Activity and Selectivity in the Metathesis of α‐Olefins

Jordan De Jesus Silva

Papers

Olefin metathesis: what have we learned about homogeneous and heterogeneous catalysts from surface organometallic chemistry?

Noncovalent Interactions Drive the Efficiency of Molybdenum Imido Alkylidene Catalysts for Olefin Metathesis

Molecular-level insight in supported olefin metathesis catalysts by combining surface organometallic chemistry, high throughput experimentation, and data analysis

Benchmarked Intrinsic Olefin Metathesis Activity: Mo vs. W

Silica‐Supported Cationic Tungsten Imido Alkylidene Stabilized by an N‐Heterocyclic Carbene Ligand Boosts Activity and Selectivity in the Metathesis of α‐Olefins