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Bifunctional Catalysis
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Bifunctional Catalysis

A special issue of Molecules (ISSN 1420-3049).

Deadline for manuscript submissions: closed (15 October 2010) | Viewed by 75940

Special Issue Editor

Prof. Dr. Takao Ikariya

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Guest Editor
Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan

Special Issue Information

Dear Colleagues,

Recent advances in green and sustainable science and technology strongly demand powerful and sophisticated catalysts with a tunable multifunction. The design and development of molecular catalysts with a bifunction based on the combination of Lewis acid and Lewis base working in concert is of ongoing interest in organic synthetic chemistry. Since the bifunctional catalysts contain two or more active sites for activation of the electrophiles and nucleophiles, they can efficiently effect a wide range of molecular transformation including C–H, C–C, C–O, or C–N bond formation by dual activation and effective accumulation of reacting substrates on the neighboring active centers in the same molecules. Thus, the rational design of the cooperating ligand that also adjust the balance of the electronic factors in the bifunctional catalysts is crucially important to exploit unprecedented catalyst performance.

Prof. Dr. Takao Ikariya
Guest Editor

Keywords

  • bifunctional catalyst
  • acid-base synergy effect
  • cooperating lignad
  • multi-metallic center catalyst
  • non-innocent ligand
  • dual activation
  • asymmetric catalysis
  • concerto molecular catalysis
  • environmental benign synthetic process

Published Papers (8 papers)

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Research

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250 KiB  
Article
Synthesis and Properties of Chiral Thioureas Bearing an Additional Function at a Remote Position Tethered by a 1,5-Disubstituted Triazole
by Kiyosei Takasu, Takumi Azuma, Iderbat Enkhtaivan and Yoshiji Takemoto
Molecules 2010, 15(11), 8327-8348; https://doi.org/10.3390/molecules15118327 - 15 Nov 2010
Cited by 6 | Viewed by 7605
Abstract
The synthesis and properties of multifunctional thioureas bearing a variety of functional groups at a position remote from the thiourea moiety are described. A 1,5-disubstituted triazole tether connected with a thiourea and another functional group was synthesized via ruthenium catalyzed Huisgen cycloaddition. We [...] Read more.
The synthesis and properties of multifunctional thioureas bearing a variety of functional groups at a position remote from the thiourea moiety are described. A 1,5-disubstituted triazole tether connected with a thiourea and another functional group was synthesized via ruthenium catalyzed Huisgen cycloaddition. We demonstrate the utility of the synthetic thioureas as asymmetric catalysts and probes for the mechanistic elucidation of the course of the Michael reaction of an α,β-unsaturated imide Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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318 KiB  
Article
Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions
by Kohzo Yoshida, Tsubasa Inokuma, Kiyosei Takasu and Yoshiji Takemoto
Molecules 2010, 15(11), 8305-8326; https://doi.org/10.3390/molecules15118305 - 15 Nov 2010
Cited by 28 | Viewed by 7124
Abstract
Organoammonium salts composed of a Brønsted acid and an anilinothiourea promoted the Michael addition of β-keto esters and α,β-unsaturated aldehydes in the presence of primary amines to give functionalized 1,4-dihydropyridines enantioselectively. With the use of the different Brønsted acids such as DFA and [...] Read more.
Organoammonium salts composed of a Brønsted acid and an anilinothiourea promoted the Michael addition of β-keto esters and α,β-unsaturated aldehydes in the presence of primary amines to give functionalized 1,4-dihydropyridines enantioselectively. With the use of the different Brønsted acids such as DFA and HBF4 with the same bifunctional thiourea, both enantiomers of 4-substituted 1,4-dihydropyridine were synthesized from the same starting materials. Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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121 KiB  
Communication
Application of Phosphine-Phosphite Ligands in the Iridium Catalyzed Enantioselective Hydrogenation of 2-Methylquinoline
by Miguel Rubio and Antonio Pizzano
Molecules 2010, 15(11), 7732-7741; https://doi.org/10.3390/molecules15117732 - 29 Oct 2010
Cited by 14 | Viewed by 7663
Abstract
The hydrogenation of 2-methylquinoline with Ir catalysts based on chiral phosphine-phosphites has been investigated. It has been observed that the reaction is very sensitive to the nature of the ligand. Optimization of the catalyst, allowed by the highly modular structure of these phosphine-phosphites, [...] Read more.
The hydrogenation of 2-methylquinoline with Ir catalysts based on chiral phosphine-phosphites has been investigated. It has been observed that the reaction is very sensitive to the nature of the ligand. Optimization of the catalyst, allowed by the highly modular structure of these phosphine-phosphites, has improved the enantioselectivity of the reaction up to 73% ee. The influence of additives in this reaction has also been investigated. Contrary to the beneficial influence observed in related catalytic systems, iodine has a deleterious effect in the present case. Otherwise, aryl phosphoric acids produce a positive impact on catalyst activity without a decrease on enantioselectivity. Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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316 KiB  
Article
Bifunctional Catalysis: Direct Reductive Amination of Aliphatic Ketones with an Iridium-Phosphate Catalyst
by Barbara Villa-Marcos, Chaoqun Li, Keith R. Mulholland, Philip J. Hogan and Jianliang Xiao
Molecules 2010, 15(4), 2453-2472; https://doi.org/10.3390/molecules15042453 - 08 Apr 2010
Cited by 52 | Viewed by 11723
Abstract
Chiral amines are one of the ubiquitous functional groups in fine chemical, pharmaceutical and agrochemical products, and the most convenient, economical, and eco-benign synthetic pathway to these amines is direct asymmetric reductive amination (DARA) of prochiral ketones. This paper shows that a wide [...] Read more.
Chiral amines are one of the ubiquitous functional groups in fine chemical, pharmaceutical and agrochemical products, and the most convenient, economical, and eco-benign synthetic pathway to these amines is direct asymmetric reductive amination (DARA) of prochiral ketones. This paper shows that a wide range of aliphatic ketones can be directly aminated under hydrogenation conditions, affording chiral amines with good to excellent yields and with enantioselectivities up to 96% ee. The catalysis is effected by the cooperative action of a cationic Cp*Ir(III) complex and its phosphate counteranion. Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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158 KiB  
Article
Catalytic Asymmetric Nitro-Mannich Reactions with a Yb/K Heterobimetallic Catalyst
by Tatsuya Nitabaru, Naoya Kumagai and Masakatsu Shibasaki
Molecules 2010, 15(3), 1280-1290; https://doi.org/10.3390/molecules15031280 - 04 Mar 2010
Cited by 21 | Viewed by 8601
Abstract
A catalytic asymmetric nitro-Mannich (aza-Henry) reaction with rare earth metal/alkali metal heterobimetallic catalysts is described. A Yb/K heterobimetallic catalyst assembled by an amide-based ligand promoted the asymmetric nitro-Mannich reaction to afford enantioenriched anti-b-nitroamines in up to 86% ee. Facile reduction of the [...] Read more.
A catalytic asymmetric nitro-Mannich (aza-Henry) reaction with rare earth metal/alkali metal heterobimetallic catalysts is described. A Yb/K heterobimetallic catalyst assembled by an amide-based ligand promoted the asymmetric nitro-Mannich reaction to afford enantioenriched anti-b-nitroamines in up to 86% ee. Facile reduction of the nitro functionality allowed for efficient access to optically active 1,2-diamines. Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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212 KiB  
Article
Catalytic Asymmetric 1,4-Additions of β-Keto Esters to Nitroalkenes Promoted by a Bifunctional Homobimetallic Co2-Schiff Base Complex
by Makoto Furutachi, Zhihua Chen, Shigeki Matsunaga and Masakatsu Shibasaki
Molecules 2010, 15(1), 532-544; https://doi.org/10.3390/molecules15010532 - 22 Jan 2010
Cited by 33 | Viewed by 9556
Abstract
Catalytic asymmetric 1,4-addition of β-keto esters to nitroalkenes is described. 2.5 mol % of a homobimetallic Lewis acid/Brønsted base bifunctional Co2-Schiff base complex smoothly promoted the reaction in excellent yield (up to 99%), diastereoselectivity, and enantioselectivity (up to >30:1 dr and [...] Read more.
Catalytic asymmetric 1,4-addition of β-keto esters to nitroalkenes is described. 2.5 mol % of a homobimetallic Lewis acid/Brønsted base bifunctional Co2-Schiff base complex smoothly promoted the reaction in excellent yield (up to 99%), diastereoselectivity, and enantioselectivity (up to >30:1 dr and 98% ee). Catalyst loading was successfully reduced to 0.1 mol %. Mechanistic studies suggested that intramolecular cooperative functions of the two Co-metal centers are important for high catalytic activity and stereoselectivity. Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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Review

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447 KiB  
Review
Development of Heterogeneous Olympic Medal Metal Nanoparticle Catalysts for Environmentally Benign Molecular Transformations Based on the Surface Properties of Hydrotalcite
by Kiyotomi Kaneda, Takato Mitsudome, Tomoo Mizugaki and Koichiro Jitsukawa
Molecules 2010, 15(12), 8988-9007; https://doi.org/10.3390/molecules15128988 - 08 Dec 2010
Cited by 41 | Viewed by 9177
Abstract
In this review, we describe the development by our research group of highly functionalized heterogeneous Olympic medal metal (gold, silver, and copper) nanoparticle catalysts using hydrotalcite as a support, aimed towards Green and Sustainable Chemistry. Olympic medal metal nanoparticles can cooperate with the [...] Read more.
In this review, we describe the development by our research group of highly functionalized heterogeneous Olympic medal metal (gold, silver, and copper) nanoparticle catalysts using hydrotalcite as a support, aimed towards Green and Sustainable Chemistry. Olympic medal metal nanoparticles can cooperate with the basic sites on the hydrotalcite surface, providing unique and high performance catalysis in environmentally-benign organic transformations such as aerobic oxidation of alcohols, lactonization of diols and selective deoxygenation of epoxides and nitro aromatic compounds. Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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135 KiB  
Review
Norcoclaurine Synthase: Mechanism of an Enantioselective Pictet-Spengler Catalyzing Enzyme
by Alessandra Bonamore, Marco Barba, Bruno Botta, Alberto Boffi and Alberto Macone
Molecules 2010, 15(4), 2070-2078; https://doi.org/10.3390/molecules15042070 - 24 Mar 2010
Cited by 38 | Viewed by 13037
Abstract
The use of bifunctional catalysts in organic synthesis finds inspiration in the selectivity of enzymatic catalysis which arises from the specific interactions between basic and acidic amino acid residues and the substrate itself in order to stabilize developing charges in the transition state. [...] Read more.
The use of bifunctional catalysts in organic synthesis finds inspiration in the selectivity of enzymatic catalysis which arises from the specific interactions between basic and acidic amino acid residues and the substrate itself in order to stabilize developing charges in the transition state. Many enzymes act as bifunctional catalysts using amino acid residues at the active site as Lewis acids and Lewis bases to modify the substrate as required for the given transformation. They bear a clear advantage over non-biological methods for their ability to tackle problems related to the synthesis of enantiopure compounds as chiral building blocks for drugs and agrochemicals. Moreover, enzymatic synthesis may offer the advantage of a clean and green synthetic process in the absence of organic solvents and metal catalysts. In this work the reaction mechanism of norcoclaurine synthase is described. This enzyme catalyzes the Pictet-Spengler condensation of dopamine with 4-hydroxyphenylacetaldehyde (4-HPAA) to yield the benzylisoquinoline alkaloids central precursor, (S)-norcoclaurine. Kinetic and crystallographic data suggest that the reaction mechanism occurs according to a typical bifunctional catalytic process. Full article
(This article belongs to the Special Issue Bifunctional Catalysis)
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