1
|
Ushimaru R. Unusual Enzymatic C-C Bond Formation and Cleavage Reactions during Natural Product Biosynthesis. Chem Pharm Bull (Tokyo) 2024; 72:241-247. [PMID: 38432903 DOI: 10.1248/cpb.c23-00889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Natural products from plants and microorganisms provide a valuable reservoir of pharmaceutical compounds. C-C bond formation and cleavage are crucial events during natural product biosynthesis, playing pivotal roles in generating diverse and intricate chemical structures that are essential for biological functions. This review summarizes our recent findings regarding biosynthetic enzymes that catalyze unconventional C-C bond formation and cleavage reactions during natural product biosynthesis.
Collapse
Affiliation(s)
- Richiro Ushimaru
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo
| |
Collapse
|
2
|
Stierle SA, Harken L, Li SM. P450 in C-C coupling of cyclodipeptides with nucleobases. Methods Enzymol 2023; 693:231-265. [PMID: 37977732 DOI: 10.1016/bs.mie.2023.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Bacterial cytochrome P450 enzymes catalyze various and often intriguing tailoring reactions during the biosynthesis of natural products. In contrast to the majority of membrane-bound P450 enzymes from eukaryotes, bacterial P450 enzymes are soluble proteins and therefore represent excellent candidates for in vitro biochemical investigations. In particular, cyclodipeptide synthase-associated cytochrome P450 enzymes have recently gained attention due to the broad spectrum of reactions they catalyze, i.e. hydroxylation, aromatization, intramolecular C-C bond formation, dimerization, and nucleobase addition. The latter reaction has been described during the biosynthesis of guanitrypmycins, guatrypmethines and guatyromycines in various Streptomyces strains, where the nucleobases guanine and hypoxanthine are coupled to cyclodipeptides via C-C, C-N, and C-O bonds. In this chapter, we provide an overview of cytochrome P450 enzymes involved in the C-C coupling of cyclodipeptides with nucleobases and describe the protocols used for the successful characterization of these enzymes in our laboratory. The procedure includes cloning of the respective genes into expression vectors and subsequent overproduction of the corresponding proteins in E. coli as well as heterologous expression in Streptomyces. We describe the purification and in vitro biochemical characterization of the enzymes and protocols to isolate the produced compounds for structure elucidation.
Collapse
Affiliation(s)
- Sina A Stierle
- Institut für Pharmazeutische Biologie und Biotechnologie, Fachbereich Pharmazie, Philipps-Universität Marburg, Marburg, Germany
| | - Lauritz Harken
- Institut für Pharmazeutische Biologie und Biotechnologie, Fachbereich Pharmazie, Philipps-Universität Marburg, Marburg, Germany
| | - Shu-Ming Li
- Institut für Pharmazeutische Biologie und Biotechnologie, Fachbereich Pharmazie, Philipps-Universität Marburg, Marburg, Germany.
| |
Collapse
|
3
|
Mouat JM, Widness JK, Enny DG, Meidenbauer MT, Awan F, Krauss TD, Weix DJ. CdS Quantum Dots for Metallaphotoredox-Enabled Cross-Electrophile Coupling of Aryl Halides with Alkyl Halides. ACS Catal 2023; 13:9018-9024. [PMID: 38283073 PMCID: PMC10812861 DOI: 10.1021/acscatal.3c01984] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Semiconductor quantum dots (QDs) offer many advantages as photocatalysts for synthetic photoredox catalysis, but no reports have explored the use of QDs with nickel catalysts for C-C bond formation. We show here that 5.7 nm CdS QDs are robust photocatalysts for photoredox-promoted cross-electrophile coupling (40 000 TON). These conditions can be utilized on small scale (96-well plate) or adapted to flow. NMR studies show that triethanolamine (TEOA) capped QDs are the active catalyst and that TEOA can displace native phosphonate and carboxylate ligands, demonstrating the importance of QD surface chemistry.
Collapse
Affiliation(s)
- Julianna M. Mouat
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706 USA
| | - Jonas K. Widness
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706 USA
| | - Daniel G. Enny
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706 USA
| | | | - Farwa Awan
- Department of Chemistry, University of Rochester, Rochester, NY 14627 USA
| | - Todd D. Krauss
- Department of Chemistry, University of Rochester, Rochester, NY 14627 USA
- Institute of Optics, University of Rochester, Rochester, NY 14627 USA
| | - Daniel J. Weix
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706 USA
| |
Collapse
|
4
|
Martín CDMG, García JIH, Bonardd S, Díaz DD. Lignin-Based Catalysts for C-C Bond-Forming Reactions. Molecules 2023; 28:molecules28083513. [PMID: 37110747 PMCID: PMC10141373 DOI: 10.3390/molecules28083513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/01/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Carbon-carbon (C-C) bond formation is the key reaction in organic synthesis to construct the carbon framework of organic molecules. The continuous shift of science and technology toward eco-friendly and sustainable resources and processes has stimulated the development of catalytic processes for C-C bond formation based on the use of renewable resources. In this context, and among other biopolymer-based materials, lignin has attracted scientific attention in the field of catalysis during the last decade, either through its acid form or as a support for metal ions and metal nanoparticles that drive the catalytic activity. Its heterogeneous nature, as well as its facile preparation and low cost, provide competitive advantages over other homogeneous catalysts. In this review, we have summarized a variety of C-C formation reactions, such as condensations, Michael additions of indoles, and Pd-mediated cross-coupling reactions that were successfully carried out in the presence of lignin-based catalysts. These examples also involve the successful recovery and reuse of the catalyst after the reaction.
Collapse
Affiliation(s)
- Cristina Del Mar García Martín
- Instituto de Bio-Orgánica Antonio González, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain
| | - José Ignacio Hernández García
- Instituto de Bio-Orgánica Antonio González, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain
- Departamento de Química Orgánica, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 3, 38206 La Laguna, Spain
| | - Sebastián Bonardd
- Instituto de Bio-Orgánica Antonio González, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain
- Departamento de Química Orgánica, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 3, 38206 La Laguna, Spain
| | - David Díaz Díaz
- Instituto de Bio-Orgánica Antonio González, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain
- Departamento de Química Orgánica, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 3, 38206 La Laguna, Spain
| |
Collapse
|
5
|
Rouvinen J, Andberg M, Pääkkönen J, Hakulinen N, Koivula A. Current state of and need for enzyme engineering of 2-deoxy-D-ribose 5-phosphate aldolases and its impact. Appl Microbiol Biotechnol 2021; 105:6215-28. [PMID: 34410440 DOI: 10.1007/s00253-021-11462-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/13/2021] [Accepted: 07/19/2021] [Indexed: 01/28/2023]
Abstract
Abstract Deoxyribose-5-phosphate aldolases (DERAs, EC 4.1.2.4) are acetaldehyde-dependent, Class I aldolases catalyzing in nature a reversible aldol reaction between an acetaldehyde donor (C2 compound) and glyceraldehyde-3-phosphate acceptor (C3 compound, C3P) to generate deoxyribose-5-phosphate (C5 compound, DR5P). DERA enzymes have been found to accept also other types of aldehydes as their donor, and in particular as acceptor molecules. Consequently, DERA enzymes can be applied in C–C bond formation reactions to produce novel compounds, thus offering a versatile biocatalytic alternative for synthesis. DERA enzymes, found in all kingdoms of life, share a common TIM barrel fold despite the low overall sequence identity. The catalytic mechanism is well-studied and involves formation of a covalent enzyme-substrate intermediate. A number of protein engineering studies to optimize substrate specificity, enzyme efficiency, and stability of DERA aldolases have been published. These have employed various engineering strategies including structure-based design, directed evolution, and recently also machine learning–guided protein engineering. For application purposes, enzyme immobilization and usage of whole cell catalysis are preferred methods as they improve the overall performance of the biocatalytic processes, including often also the stability of the enzyme. Besides single-step enzymatic reactions, DERA aldolases have also been applied in multi-enzyme cascade reactions both in vitro and in vivo. The DERA-based applications range from synthesis of commodity chemicals and flavours to more complicated and high-value pharmaceutical compounds. Key points • DERA aldolases are versatile biocatalysts able to make new C–C bonds. • Synthetic utility of DERAs has been improved by protein engineering approaches. • Computational methods are expected to speed up the future DERA engineering efforts. Graphical abstract ![]()
Collapse
|
6
|
Voutilainen S, Heinonen M, Andberg M, Jokinen E, Maaheimo H, Pääkkönen J, Hakulinen N, Rouvinen J, Lähdesmäki H, Kaski S, Rousu J, Penttilä M, Koivula A. Substrate specificity of 2-deoxy-D-ribose 5-phosphate aldolase (DERA) assessed by different protein engineering and machine learning methods. Appl Microbiol Biotechnol 2020; 104:10515-10529. [PMID: 33147349 PMCID: PMC7671976 DOI: 10.1007/s00253-020-10960-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/01/2020] [Accepted: 10/12/2020] [Indexed: 11/29/2022]
Abstract
In this work, deoxyribose-5-phosphate aldolase (Ec DERA, EC 4.1.2.4) from Escherichia coli was chosen as the protein engineering target for improving the substrate preference towards smaller, non-phosphorylated aldehyde donor substrates, in particular towards acetaldehyde. The initial broad set of mutations was directed to 24 amino acid positions in the active site or in the close vicinity, based on the 3D complex structure of the E. coli DERA wild-type aldolase. The specific activity of the DERA variants containing one to three amino acid mutations was characterised using three different substrates. A novel machine learning (ML) model utilising Gaussian processes and feature learning was applied for the 3rd mutagenesis round to predict new beneficial mutant combinations. This led to the most clear-cut (two- to threefold) improvement in acetaldehyde (C2) addition capability with the concomitant abolishment of the activity towards the natural donor molecule glyceraldehyde-3-phosphate (C3P) as well as the non-phosphorylated equivalent (C3). The Ec DERA variants were also tested on aldol reaction utilising formaldehyde (C1) as the donor. Ec DERA wild-type was shown to be able to carry out this reaction, and furthermore, some of the improved variants on acetaldehyde addition reaction turned out to have also improved activity on formaldehyde. KEY POINTS: • DERA aldolases are promiscuous enzymes. • Synthetic utility of DERA aldolase was improved by protein engineering approaches. • Machine learning methods aid the protein engineering of DERA.
Collapse
Affiliation(s)
- Sanni Voutilainen
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
| | - Markus Heinonen
- Department of Computer Science, Aalto University, Espoo, Finland
- Helsinki Institute for Information Technology, Espoo, Finland
| | - Martina Andberg
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Emmi Jokinen
- Department of Computer Science, Aalto University, Espoo, Finland
| | - Hannu Maaheimo
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Johan Pääkkönen
- Department of Chemistry, University of Eastern Finland, PO Box 111, FI-80101, Joensuu, Finland
| | - Nina Hakulinen
- Department of Chemistry, University of Eastern Finland, PO Box 111, FI-80101, Joensuu, Finland
| | - Juha Rouvinen
- Department of Chemistry, University of Eastern Finland, PO Box 111, FI-80101, Joensuu, Finland
| | - Harri Lähdesmäki
- Department of Computer Science, Aalto University, Espoo, Finland
| | - Samuel Kaski
- Department of Computer Science, Aalto University, Espoo, Finland
- Helsinki Institute for Information Technology, Espoo, Finland
| | - Juho Rousu
- Department of Computer Science, Aalto University, Espoo, Finland
- Helsinki Institute for Information Technology, Espoo, Finland
| | - Merja Penttilä
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Anu Koivula
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| |
Collapse
|
7
|
Denner C, Gintner M, Kählig H, Wrodnigg TM, Schmid W. Indium-mediated allylation of disaccharides. Carbohydr Res 2020; 498:108170. [PMID: 33068775 DOI: 10.1016/j.carres.2020.108170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/24/2020] [Accepted: 09/30/2020] [Indexed: 11/26/2022]
Abstract
The indium-mediated allylation followed by ozonolysis has been applied for the elongation of different disaccharides such as cellobiose, lactose and maltose. This reaction sequence and per-O-acetylation produced the expected mixture of α/β-pyranoid as well as α/β-furanoid isomers. The main product in all cases adopted the β-pyranose form and could be isolated and fully characterized with the help of NMR-spin simulations. Thorough investigation of the side products throughout optimization of the conditions for the ozonolysis resulted in the discovery of a novel 12 membered bridged disaccharide.
Collapse
Affiliation(s)
- Christian Denner
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria.
| | - Manuel Gintner
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria
| | - Hanspeter Kählig
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria
| | - Tanja M Wrodnigg
- Glycogroup, Institute of Chemistry and Technology for Biobased Systems, Graz University of Technology, Stremayrgasse 9, A-8010, Graz, Austria
| | - Walther Schmid
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria
| |
Collapse
|
8
|
Abstract
The indium-mediated allylation reaction has been applied to melibiose, a disaccharidic substrate. This elongation methodology allows for a short, efficient and diastereoselective approach towards complex glycosylated carbohydrate structures. The stereochemical outcome of the key intermediates, allylated disaccharides, has been determined by X-ray analysis. Ozonolysis of the introduced double bond yielded the unprotected elongated disaccharides in the equilibrium of the pyranoid as well as furanoid isomers in both anomeric forms, respectively. Per-O-acetylation has been performed to facilitate separation of the isomeric mixture for structural identification. The main product revealed to adopt a β-pyranoid form of the elongated unit at the reducing end of the disaccharide.
Collapse
Affiliation(s)
- Christian Denner
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria
| | - Manuel Gintner
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria
| | - Hanspeter Kählig
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria
| | - Walther Schmid
- Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, A-1090, Vienna, Austria
| |
Collapse
|
9
|
Abstract
C-C bond-forming reactions often require nucleophilic carbon species rarely compatible with aqueous reaction media, thus restricting their appearance in biocatalysis. Here we report the use of nitroalkanes as a structurally versatile class of nucleophilic substrates for C-C bond formation catalyzed by variants of the β-subunit of tryptophan synthase (TrpB). The enzymes accept a wide range of nitroalkanes to form noncanonical amino acids, here the nitro group can serve as a handle for further modification. Using nitroalkane nucleophiles greatly expands the scope of compounds made by TrpB variants and establishes nitroalkanes as a valuable substrate class for biocatalytic C-C bond formation.
Collapse
Affiliation(s)
- David K. Romney
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Nicholas S. Sarai
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| |
Collapse
|
10
|
Xu W, Yoshikai N. Cobalt-catalyzed directed C-H alkenylation of pivalophenone N-H imine with alkenyl phosphates. Beilstein J Org Chem 2018; 14:709-715. [PMID: 29719569 PMCID: PMC5905286 DOI: 10.3762/bjoc.14.60] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/14/2018] [Indexed: 11/24/2022] Open
Abstract
A cobalt–N-heterocyclic carbene (NHC) catalyst efficiently promotes an ortho C–H alkenylation reaction of pivalophenone N–H imine with an alkenyl phosphate. The reaction tolerates various substituted pivalophenone N–H imines as well as cyclic and acyclic alkenyl phosphates.
Collapse
Affiliation(s)
- Wengang Xu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Naohiko Yoshikai
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| |
Collapse
|
11
|
Abstract
The achievements in the synthesis of carboxylic acids and esters from CO2 have been summarized and discussed.
Collapse
Affiliation(s)
- Xiao-Feng Wu
- Department of Chemistry, Zhejiang Sci-Tech University, Xiasha Campus, Hangzhou, 310018, People's Republic of China.
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059, Rostock, Germany.
| | - Feng Zheng
- Hangzhou Branch of Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 600 No. 21 Street, Hangzhou, China.
| |
Collapse
|
12
|
Abstract
Over the last decades, iron-catalyzed cross-couplings have emerged as an important tool for the formation of C-C bonds. A wide variety of alkenyl, aryl, and alkyl (pseudo)halides have been coupled to organometallic reagents, the most currently used being Grignard reagents. Particular attention has been devoted to the development of iron catalysts for the functionalization of alkyl halides that are generally challenging substrates in classical cross-couplings. The high functional group tolerance of iron-catalyzed cross-couplings has encouraged organic chemists to use them in the synthesis of bioactive compounds. Even if some points remain obscure, numerous studies have been carried out to investigate the mechanism of iron-catalyzed cross-coupling and several hypotheses have been proposed.
Collapse
Affiliation(s)
- Amandine Guérinot
- Laboratoire de Chimie Organique, Institute of Chemistry, Biology and Innovation (CBI)-UMR 8231, ESPCI Paris/CNRS/PSL* Research Institute, 10 rue Vauquelin, 75231, Paris Cedex 05, France.
| | - Janine Cossy
- Laboratoire de Chimie Organique, Institute of Chemistry, Biology and Innovation (CBI)-UMR 8231, ESPCI Paris/CNRS/PSL* Research Institute, 10 rue Vauquelin, 75231, Paris Cedex 05, France
| |
Collapse
|
13
|
Szudkowska-Frątczak J, Taczała M, Pawluć P. 1-(Triethoxysilyl)buta-1,3-dienes-New Building Blocks for Stereoselective Synthesis of Unsymmetrical ( E, E)-1,4-Disubstituted 1,3-dienes. Materials (Basel) 2015; 8:7250-6. [PMID: 28793635 DOI: 10.3390/ma8115378] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/14/2015] [Indexed: 11/28/2022]
Abstract
A convenient methodology for the highly stereoselective synthesis of unsymmetrical (1E,3E)-1,4-disubstituted 1,3-dienes based on palladium-catalyzed Hiyama cross-coupling reaction of 1-(triethoxysilyl)-substituted buta-1,3-dienes with aryl iodides is reported.
Collapse
|
14
|
Abstract
Nitroalkenes are easily accessible in high variety by condensation of aldehydes with aliphatic nitroalkanes. They belong to the group of activated alkenes that can be hydrodimerized by cathodic reduction. There are many olefins with different electron withdrawing groups used for cathodic hydrodimerization, but not much is known about the behaviour of the nitro group. Synthetic applications of this group could profit from the easy access to nitroolefins in large variety, the C–C bond formation with the introduction of two nitro groups in a 1,4-distance and the conversions of the nitro group by reduction to oximes and amines, the conversion into aldehydes and ketones via the Nef reaction and base catalyzed condensations at the acidic CH bond. Eight 1-aryl-2-nitro-1-propenes have been electrolyzed in an undivided electrolysis cell to afford 2,5-dinitro-3,4-diaryl hexanes in high yield. The 4-methoxy-, 4-trifluoromethyl-, 2-chloro- and 2,6-difluorophenyl group and furthermore the 2-furyl and 2-pyrrolyl group have been applied. The reaction is chemoselective as only the double bond but not the nitro group undergoes reaction, is regioselective as a ß,ß-coupling with regard to the nitro group and forms preferentially two out of six possible diastereomers as major products.
Collapse
Affiliation(s)
- Michael Weßling
- Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität, Correns-Straße 40, 48149 Münster, Germany
| | - Hans J Schäfer
- Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität, Correns-Straße 40, 48149 Münster, Germany
| |
Collapse
|
15
|
Tejo C, Sim XR, Lee BR, Ayers BJ, Leung CH, Ma DL, Chan PW. Iminoiodane- and Brønsted base-mediated cross dehydrogenative coupling of cyclic ethers with 1,3-dicarbonyl compounds. Molecules 2015; 20:13336-53. [PMID: 26205058 DOI: 10.3390/molecules200713336] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A one-pot, two-step approach to prepare 2-tetrahydrofuran and -pyran substituted 1,3-dicarbonyl compounds by PhI=NTs-mediated amination/Brønsted base-catalyzed cross dehydrogenative coupling (CDC) reaction of the cyclic ether and 1,3-dicarbonyl derivative under mild conditions is reported. The reaction is compatible with a variety of cyclic ethers and 1,3-dicarbonyl compounds, affording the corresponding coupled products in moderate to good yields of up to 80% over two steps.
Collapse
|
16
|
Affiliation(s)
- Rafael Gramage-Doria
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam Science Park 904, 1098 XH, Amsterdam (The Netherlands) E-mail:
| |
Collapse
|
17
|
Abstract
Ruthenium-catalyzed transfer hydrogenation of diverse π-unsaturated reactants in the presence of aldehydes provides products of carbonyl addition. Dehydrogenation of primary alcohols in the presence of the same π-unsaturated reactants provides identical products of carbonyl addition. In this way, carbonyl addition is achieved from the alcohol or aldehyde oxidation level in the absence of stoichiometric organometallic reagents or metallic reductants. In this account, the discovery of ruthenium-catalyzed C-C bond-forming transfer hydrogenations and the recent development of diastereo- and enantioselective variants are discussed.
Collapse
Affiliation(s)
- Joseph Moran
- Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-1167, USA
| | - Michael J. Krische
- Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-1167, USA
| |
Collapse
|