Special Issue "Bifunctional Catalysis"

Guest Editor
Prof. Dr. Takao Ikariya
Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Japan
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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

Submission

• 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

Manuscript ID: Molecules-bifuncat-200916-uk-Xiao
Type of Paper: Article
Title: Asymmetric Direct Reductive Amination with Bifunctional Catalysts
Authors: Barbara Villa-Marcos, Chaoqun Li and Jianliang Xiao
Affiliation: Liverpool Centre for Materials and Catalysis, Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.; E-Mail: J.Xiao@liverpool.ac.uk
Abstract: Chiral amines are one of the ubiquitous functional groups in fine chemical, agrochemical and pharmaceutical products, and the most convenient, economical, and eco-benign synthetic pathway to these amines is direct asymmetric reductive amination (DARA) of prochiral ketones. We have recently communicated that efficient DARA is effected by cooperative catalysis of a Cp*Ir(III) complex and a chiral Brønsted acid (J. Am. Chem. Soc. 2009, 131, 6967). In this paper, we present details on how the catalyst can be exploited in DARA of aliphatic ketones.

Title: Asymmetric Transfer Hydrogenation of Prochiral Ketones in Aqueous Media with Chiral Water-Soluble and Heterogenized Ligand-RhCp* Bifunctional Catalysts
Authors: Angélica Barrón-Jaime ¹, Oscar F. Narvaez-Garayzar ¹, Jorge González ², Valentín Ibarra-Galván ², Gerardo Aguirre ¹, Miguel Parra-Hake ¹, Daniel Chávez ¹ and Ratnasamy Somanathan ¹
Affiliations: ¹ Centro de Graduados e Investigación, Instituto Tecnológico de Tijuana, Apartado Postal 1166, Tijuana, B. C. 22000, Mexico; E-Mail: somanatha@sundown.sdsu.edu (R.S.)
² Facultad de Ciencias Químicas, Universidad de Colima, Km 9 Carretera Coquimatlán-Colima, Coquimatlán, Col. 28400, Mexico
Abstract: Asymmetric transfer hydrogenation (ATH) of prochiral aromatic ketones was carried out with a water soluble complex of Rh^IIICp* and mono nitrosulfonamide bidentate ligand (1R,2R)-N-(2-aminocyclohexyl)-4-nitrobenzenesulfonamide derived from chiral cyclohexane-1,2-diamine. Aqueous sodium formate was used as the hydride source. The reaction afforded the chiral alcohols in good enatioselectivities (79-93%) and yields (>99%). The modified monosulfonamide ligand was also covalently immobilized on solid phase, such as silica, resin and microporous SBA-15, and then explored as a catalyst with Rh^IIICp* in the ATH of acetophenone.
Keywords: Asymetric hydrogenation, prochiral ketones, chiral ligands, nitrosulfonamide, heterogenized ligands, Rh^IIICp*

Type of Paper: Article
Title: Synthesis and Property of Chiral Thioureas Bearing An Additional Function at A Remote Position Tethered by 1,5-Disubstituted Triazole
Author: Yoshiji Takemoto
Affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan; E-Mail: takemoto@pharm.kyoto-u.ac.jp
Abstract: Thiourea-amine bifunctional catalysts, which were developed by our group, possess isolated acidic and basic functional groups in the same molecule. In those, two functional moieties are placed at neighboring position so as to entropically activate the bimolecular reaction. Thioureas bearing two activating site at a comparably remote position have been less explored. Taking lessons in a catalyst design from natural enzymes, the important and challenging tasks would be adequate design of the tether, which must display conformational flexibility/rigidity appropriately to afford an organized reaction space. For the special issue, we are planning to report synthesis and property of new bifunctional thioureas whose activating sites are placed at a sequentially remote position (7~8 atoms’ tether length). A part of the above study will be published as a communication in Tetrahedron Letters. Further studies including full experimental section and detailed discussion will be described.