Oxidative coupling reactions at ruthenium(0) and their applications to catalytic homo- and cross-dimerizations¶

Hirano, Masafumi; Komiya, Sanshiro

doi:10.1016/j.ccr.2015.07.008

Cited by 40 publications

(33 citation statements)

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“…We wondered if we could circumvent the use of aluminum alkyls in this protocol by exploiting a discrete and identifiable Co(I)/Co(III)-redox cycle (Figure 1) as a possible pathway for this reaction that maybe approached differently by modifying the reaction conditions. This would involve an oxidative dimerization of the two olefins assisted by the low-valent cobalt species ( 3 + 4 + 6 —> 7 ), a mechanistic possibility that has been advanced before in other ruthenium- 9 and cobalt- 10 catalyzed heterodimerization reactions, but without much supporting evidence. Even though low-valent cobalt phosphine complexes have been used extensively in catalytic carbon-carbon bond-forming reactions, 11 these reagents are almost invariably generated in situ in the presence of excess reducing agents and other metal salts, and the oxidation state of cobalt and the nature of the intermediates (radicals or low-valent organometallic C-Co species) in many of these reactions are often open to speculation.…”

Section: Resultsmentioning

confidence: 99%

Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes

et al. 2017

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1,3-Dienes are ubiquitous and easily synthesized starting materials for organic synthesis and alkyl acrylates are among the most abundant and cheap feedstock carbon sources. A practical, highly enantioselective union of these two readily available precursors giving valuable, enantio-pure skipped 1,4-diene esters (with two configurationally defined double bonds) is reported. The process uses commercially available cobalt salts and chiral ligands. As illustrated by the use of 20 different substrates including 17 prochiral 1,3-dienes and 3 different acrylates, this heterodimerization reaction is tolerant of a number of common organic functional groups (e.g., aromatic substituents, halides, isolated mono- and di-substituted double bonds, esters, silyl ethers and silyl enol ethers). The novel results including ligand, counter ion and solvent effects uncovered during the course of these investigations show a unique role of a possible cationic Co(I) intermediate in these reactions. The rational evolution of a mechanism-based strategy that led to the eventual successful outcome and the attendant support studies may have further implications for the expanding use of low-valent group 9 metal complexes in organic synthesis.

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Section: Resultsmentioning

confidence: 99%

Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes

et al. 2017

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“…Ruthenium complexes are some of the most extensively investigated catalysts for organic synthesis, and five-membered ruthenacycles generated by oxidative cyclization of unsaturated molecules are some of the key intermediates in catalytic reactions. However, the formation of ruthenacycles has been mostly limited to olefinic and acetylenic substrates using CpRu II species or Ru(0) carbonyls, and oxidative cyclization containing polar double bonds such as CO and CN has been limited partially because these Ru(II) or Ru(0) complexes have relatively weak reducing ability. Actually, a limited number of papers have been reported on the hetero-Pauson–Khand-type [2 + 2 + 1] cycloaddition and oxidative cyclization of dienes with carbonyl compounds .…”

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confidence: 99%

Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO₂

2018

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By using a zerovalent, electron-rich ruthenium complex bearing a tetradentate phosphine ligand, a fivemembered ruthenalactone was generated by oxidative cyclization of ethylene and CO 2 . This ruthenalactone underwent thermal, reversible β-H elimination to afford an acrylato(hydrido)ruthenium(II) complex, which liberated acrylate salt on treatment with a base. The reaction was successfully applied to the first ruthenium-catalyzed synthesis of an acrylate salt from ethylene and CO 2 . This study demonstrated the feasibility of the electron-rich ruthenium(0) complex as a catalyst in CO 2 -fixation chemistry.

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“…According to the present and our previous results, 5 the catalytic cycle shown in Scheme 3 is consistent for the coupling (6) Scheme 2. Synthesis of pesticide lead 6ab.…”

Section: ¹1mentioning

confidence: 53%

“…4 In fact, while reaction of 2a with methyl methacrylate (3a) produced 4aa in high yield, even closely related methacryl amide (3b) remained unreacted (Scheme 1). As part of our ongoing program to prepare new (naphthalene)ruthenium(0) complexes having a cyclic diene ligand, 5 we prepared [Ru(η 6 -naphthalene)(rac-η 4 -bicyclo[3.3.1]-nona-2,6-diene)] (1b). 6 In this paper, we report 1b to be a more tolerant catalyst than 1a for the C3-selective coupling of the unsaturated heterocyclic 5-membered ring compounds.…”

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Ru(0)-catalyzed C3-selective Coupling Reactions of Unsaturated 5-Membered Heterocycles with Methyl Methacrylate and Methacryl Amide

et al. 2017

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C3-selective direct coupling reactions of unsaturated 5-membered heterocycles such as 2,5-dihydrofuran, N-tosyl-2,5-dihydropyrrole, and 3-sulfolene with methyl methacrylate or methacryl amide are catalyzed by [Ru(η 6 -naphthalene)(η 4 -bicyclo[3.3.1]nona-2,6-diene)] (1b). As an application of this method, a pesticide lead, 2-methyl-3-(tetrahydrofuran-3-yl)propanamide (6ab) is prepared in 2 steps from 2,5-dihydrofuran in 62% total yield.Keywords: C3-selective coupling | Ruthenium | Pesticide lead Although C3-substituted 5-membered heterocyclic compounds are important substructures for many natural products, biologically active compounds, and pharmaceutical molecules, direct introduction of a substituent at the C3 position has remained difficult.1 As an example, Satoh, Miura, and coworkers recently reported the C3 coupling reaction of maleimides with acrylates (eq 1). Although this C3-selective coupling of 2a showed a broad scope for conjugated dienes, the substrate scope for conjugated carbonyl compounds was limited.4 In fact, while reaction of 2a with methyl methacrylate (3a) produced 4aa in high yield, even closely related methacryl amide (3b) remained unreacted (Scheme 1). As part of our ongoing program to prepare new (naphthalene)ruthenium (0) In this paper, we report 1b to be a more tolerant catalyst than 1a for the C3-selective coupling of the unsaturated heterocyclic 5-membered ring compounds.Reaction of 2a with 3a in THF at 0°C catalyzed by 1b (1 mol %) dominantly gave the C3-coupling product 5aa in 65% yield in 4 h ( Table 1). 6 A similar treatment of 2a with 3b gave the C3-coupling product 5ab in 75% yield. The product 5ab was fully characterized by 13 C HETCOR, and HRMS. The pNOESY experiment supported the E-configuration of the C=C bond. Note that catalyst 1a did not produce 5ab at all (Scheme 1). The coupling reaction of 2a with acryl amide (3c) failed even when 1b was used as the catalyst. The methyl substituent at the α-position in amide was required in this reaction. Complex 1b also catalyzed the C3-selective coupling of N-tosyl-2,5-dihydropyrrole (2b) with 3a to give 5ba in 99% yield. Note that catalyst 1a did not catalyze this reaction at all. Similarly, 2b also reacted with 3b in the presence of 1b as the catalyst to give 5bb in 82% yield. However, neither methyl acrylate (3d) nor methyl α-ethylacrylate (3e) produced the coupling product with 2b.Reaction of 3-sulfolene (2c) with 3a also produced 5ca in 82% yield. Catalyst 1a did not give the coupling product at all. Single crystals of 5ca were obtained by recrystallization from cold hexane as white needles, and whose molecular structure by X-ray analysis is depicted in Figure 1. As expected, 3a attacked the C3 position in 2c. The stereochemistry of the C(5)=C(6) bond was confirmed as the E-form.In the Rh-catalyzed conjugated addition of arylboronic acid, a portion of 3-sulfolene converted into the unstable isomer, 2-sulfolene, by base catalysis and the resulting 2-sulfolene did react with arylboronic acid effectively. 7In order to check ...

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Oxidative coupling reactions at ruthenium(0) and their applications to catalytic homo- and cross-dimerizations¶

Cited by 40 publications

References 138 publications

Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes

Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes

Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO₂

Ru(0)-catalyzed C3-selective Coupling Reactions of Unsaturated 5-Membered Heterocycles with Methyl Methacrylate and Methacryl Amide

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Oxidative coupling reactions at ruthenium(0) and their applications to catalytic homo- and cross-dimerizations¶

Cited by 40 publications

References 138 publications

Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes

Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes

Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO2

Ru(0)-catalyzed C3-selective Coupling Reactions of Unsaturated 5-Membered Heterocycles with Methyl Methacrylate and Methacryl Amide

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Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO₂