1
|
Zorba L, Egaña E, Gómez-Bengoa E, Vougioukalakis GC. Zinc Iodide Catalyzed Synthesis of Trisubstituted Allenes from Terminal Alkynes and Ketones. ACS OMEGA 2021; 6:23329-23346. [PMID: 34549133 PMCID: PMC8444324 DOI: 10.1021/acsomega.1c03092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 07/13/2021] [Indexed: 05/03/2023]
Abstract
A straightforward, user-friendly, efficient protocol for the one pot, ZnI2-catalyzed allenylation of terminal alkynes with pyrrolidine and ketones, toward trisubstituted allenes, is described. Trisubstituted allenes can be obtained under either conventional heating or microwave irradiation conditions, which significantly reduces the reaction time. A sustainable, widely available, and low-cost metal salt catalyst is employed, and the reactions are carried out under solvent-free conditions. Among others, synthetically valuable allenes bearing functionalities such as amide, hydroxyl, or phthalimide can be efficiently prepared. Mechanistic experiments, including kinetic isotope effect measurements and density functional theory (DFT) calculations, suggest a rate-determining [1,5]-hydride transfer during the transformation of the intermediate propargylamine to the final allene.
Collapse
Affiliation(s)
- Leandros
P. Zorba
- Laboratory
of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens, Greece
| | - Eunate Egaña
- Department
of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
| | - Enrique Gómez-Bengoa
- Department
of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
| | - Georgios C. Vougioukalakis
- Laboratory
of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens, Greece
| |
Collapse
|
2
|
Beerhues J, Walter RRM, Aberhan H, Neubrand M, Porré M, Sarkar B. Spotlight on Ligand Effects in 1,2,3-Triazolylidene Gold Complexes for Hydroamination Catalysis: Synthesis and Catalytic Application of an Activated MIC Gold Triflimide Complex and Various MIC Gold Chloride Complexes. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julia Beerhues
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart, D-70569 Stuttgart, Germany
- Institut für Chemie und Biochemie, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Robert R. M. Walter
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart, D-70569 Stuttgart, Germany
| | - Hannes Aberhan
- Institut für Chemie und Biochemie, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Maren Neubrand
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart, D-70569 Stuttgart, Germany
| | - Marre Porré
- Institut für Chemie und Biochemie, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Biprajit Sarkar
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart, D-70569 Stuttgart, Germany
- Institut für Chemie und Biochemie, Freie Universität Berlin, D-14195 Berlin, Germany
| |
Collapse
|
3
|
Hoyer C, Schwerk P, Suntrup L, Beerhues J, Nössler M, Albold U, Dernedde J, Tedin K, Sarkar B. Synthesis, Characterization, and Evaluation of Antibacterial Activity of Ferrocenyl‐1,2,3‐Triazoles, Triazolium Salts, and Triazolylidene Complexes of Gold(
i
) and Silver(
i
). Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Carolin Hoyer
- Institut für Chemie und Biochemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Peter Schwerk
- Institut für Mikrobiologie und Tierseuchen Freie Universität Berlin Robert-von-Ostertag-Str. 7–13 14163 Berlin Germany
| | - Lisa Suntrup
- Institut für Chemie und Biochemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Julia Beerhues
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Maite Nössler
- Institut für Chemie und Biochemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Uta Albold
- Institut für Chemie und Biochemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Jens Dernedde
- Institut für Laboratoriumsmedizin Klinische Chemie und Pathobiochemie Charité-Universitätsmedizin Berlin Corporate member of Freie Universität Berlin Humboldt-Universität zu Berlin, and Berlin Institute of Health Augustenburger Platz 1 13353 Berlin Germany
| | - Karsten Tedin
- Institut für Mikrobiologie und Tierseuchen Freie Universität Berlin Robert-von-Ostertag-Str. 7–13 14163 Berlin Germany
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| |
Collapse
|
4
|
Ang ZZ, Laxmi S, León F, Kooij JEM, García F, England J. Mechanochemical Synthesis of Tripodal Tris[4-(1,2,3-triazol-5-ylidene)methyl]amine Mesoionic Carbene Ligands and Their Complexation with Silver(I). Inorg Chem 2021; 60:3556-3564. [PMID: 33629844 DOI: 10.1021/acs.inorgchem.0c02429] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The conjugate acids of 1,2,3-triazolylidene mesoionic carbenes can be prepared in a straightforward fashion by alkylation of 1-substituted 1,2,3-triazoles. However, this becomes a much more challenging proposition when other nucleophilic centers are present, which has curtailed the development of ligands containing multiple 1,2,3-triazolylidene donors. Herein, methylation of a series of tris[(1-aryl-1,2,3-triazol-4-yl)methyl]amines possessing both electron-rich and electron-deficient aromatic substituents, using Me3OBF4, is shown to proceed with much higher chemoselectivity under mechanochemical conditions than when conducted in solution. This provides a means to reliably access a series of tricationic tris[4-(1,2,3-triazolium)methyl]amines in good yields. DFT calculations suggest that a potential reason for this change in regioselectivity is the difference between the background dielectric of the DCM solution versus the solid state, which is predicted to have a large effect on the relative thermodynamic driving force for alkylation of the tertiary amine center versus the triazole rings. Homoleptic silver complexes of the triazolylidene ligands derived therefrom, of formulas [Ag3(1a-d)2](X)3 (X- = BF4-, TfO-), have been isolated and fully characterized. In the case of the ligand bearing the smallest aryl substituents, 1b, argentophilic interactions yield a triangular Ag3 core. The [Ag3(1a-d)2](X)3 silver salts are viable agents for transmetalation to other transition metals, demonstrated here for cobalt. In the case of 1a, the complex [CoII(1a)(NCMe)](OTf)2 was obtained. Therein, the bulky mesityl substituents enforce a tetrahedral geometry, in which only the triazolylidene donors of 1a coordinate (i.e., it acts as a tridentate ligand). Transmetalation of the less sterically encumbered ligand 1b yields six-coordinate cobalt(III) complexes, [CoIII(1b)(Cl)(NCMe)](OTf)2 and [CoIII(1b)(NCMe)2](OTf)3, in which the ligand coordinates in a tetradentate fashion. These are the first examples of tris(1,2,3-triazolylidene) ligands containing an additional coordinating heteroatom and, more generally, of tetradentate 1,2,3-triazolylidene ligands. Crucially, we believe that the divergent chemoselectivity under mechanochemical conditions (vs conventional solution-based chemistry) demonstrated herein offers a pathway by which other challenging synthetic targets, including further multidentate carbene ligands, can be prepared in superior yields.
Collapse
Affiliation(s)
- Zhi Zhong Ang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Shoba Laxmi
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Félix León
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Josephine E M Kooij
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Felipe García
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Jason England
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| |
Collapse
|
5
|
Synthesis, structural diversity, and applications of mesoionic 1,2,3-triazol-5-ylidene metal complexes, an update (2017–2020). Polyhedron 2021. [DOI: 10.1016/j.poly.2020.114935] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
6
|
Gangwar MK, Butcher RJ. Axially chiral bis-1,2,3-Triazol-4-ylidene–Ag(I)-MIC and, bis-Au(I)-MIC complexes of (R)-BINOL and (-)-Menthol scaffold: Synthesis, structure, and characterizations. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2020.121626] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
7
|
Haraguchi R, Yamazaki T, Torita K, Ito T, Fukuzawa SI. Planar-chiral ferrocene-based triazolylidene copper complexes: synthesis, characterization, and catalysis in asymmetric borylation of α,β-unsaturated ester. Dalton Trans 2020; 49:17578-17583. [PMID: 33231226 DOI: 10.1039/d0dt03213a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
1,2,3-Triazol-5-ylidenes have recently attracted considerable attention as versatile ligands because of their strong electron-donating properties and structural diversities. While some efforts have been devoted to the development of chiral triazolylidene-metal complexes, there is no example achieving asymmetric induction by base-metal complexes with triazolylidene ligands. Herein, we synthesized planar-chiral ferrocene-based triazolylidene copper complexes, which enabled the asymmetric borylation of methyl cinnamate with bis(pinacolato)diboron with good enantioselectivity.
Collapse
Affiliation(s)
- Ryosuke Haraguchi
- Department of Applied Chemistry, Faculty of Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan.
| | | | | | | | | |
Collapse
|
8
|
Abstract
Three- and four-membered rings, widespread motifs in nature and medicinal chemistry, have fascinated chemists ever since their discovery. However, due to energetic considerations, small rings are often difficult to assemble. In this regard, homogeneous gold catalysis has emerged as a powerful tool to construct these highly strained carbocycles. This review aims to provide a comprehensive summary of all the major advances and discoveries made in the gold-catalyzed synthesis of cyclopropanes, cyclopropenes, cyclobutanes, cyclobutenes, and their corresponding heterocyclic or heterosubstituted analogs.
Collapse
Affiliation(s)
- Mauro Mato
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.,Departament de Quı́mica Analı́tica i Quı́mica Orgànica, Universitat Rovira i Virgili, C/Marcel·li Domingo s/n, 43007 Tarragona, Spain
| | - Allegra Franchino
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.,Departament de Quı́mica Analı́tica i Quı́mica Orgànica, Universitat Rovira i Virgili, C/Marcel·li Domingo s/n, 43007 Tarragona, Spain
| | - Cristina Garcı A-Morales
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.,Departament de Quı́mica Analı́tica i Quı́mica Orgànica, Universitat Rovira i Virgili, C/Marcel·li Domingo s/n, 43007 Tarragona, Spain
| | - Antonio M Echavarren
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.,Departament de Quı́mica Analı́tica i Quı́mica Orgànica, Universitat Rovira i Virgili, C/Marcel·li Domingo s/n, 43007 Tarragona, Spain
| |
Collapse
|
9
|
Abstract
Four carbon ring systems are frequently present in natural products with remarkable biological activities such as terpenoids, alkaloids, and steroids. The development of new strategies for the assembly of these structures in a rapid and efficient manner has attracted the interest of synthetic chemists for a long time. The current research is focused mainly on the development of synthetic methods that can be performed under mild reaction conditions with a high tolerance to functional groups. In recent years, gold complexes have turned into excellent candidates for this aim, owing to their high reactivity, and are thus capable of promoting a wide range of transformations under mild conditions. Their remarkable efficiency has been thoroughly demonstrated in the synthesis of complex organic molecules from simple starting materials. This review summarizes the main synthetic strategies described for gold-catalyzed four-carbon ring formation, as well as their application in the synthesis of natural products.
Collapse
|
10
|
Chen BL, Zhang Y, Lei YR, Wang HM, Chen Z. An allenylidene Au(i) catalyst derived from triazole units and its initial application. Chem Commun (Camb) 2020; 56:5787-5790. [PMID: 32322850 DOI: 10.1039/d0cc00429d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
An allenylidene Au(i) catalyst based on triazolylidene moieties, featuring the high σ-donating ability (comparable to that of other NHC ligands) and largely enhanced π-accepting ability of its ligand, was developed for the first time. As compared with the extant gold complexes such as IPrAuCl, Ph3PAuCl and (PhO)3PAuCl, these allenylidene Au(i) catalysts exhibited superior catalytic activities in the gold-catalyzed Nazarov reaction of aryl enones.
Collapse
Affiliation(s)
- Bai-Ling Chen
- Department of Chemistry, Renmin University of China, 59# Zhongguanchun street, Haidian District, Beijing 100872, China.
| | - Yuan Zhang
- Department of Chemistry, Renmin University of China, 59# Zhongguanchun street, Haidian District, Beijing 100872, China.
| | - Ya-Ru Lei
- Department of Chemistry, Renmin University of China, 59# Zhongguanchun street, Haidian District, Beijing 100872, China.
| | - Hui-Ming Wang
- Department of Chemistry, Renmin University of China, 59# Zhongguanchun street, Haidian District, Beijing 100872, China.
| | - Zili Chen
- Department of Chemistry, Renmin University of China, 59# Zhongguanchun street, Haidian District, Beijing 100872, China.
| |
Collapse
|
11
|
Budagumpi S, Keri RS, Achar G, Brinda KN. Coinage Metal Complexes of Chiral N‐Heterocyclic Carbene Ligands: Syntheses and Applications in Asymmetric Catalysis. Adv Synth Catal 2020. [DOI: 10.1002/adsc.201900859] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Srinivasa Budagumpi
- Centre for Nano and Material SciencesJain University, Jain Global Campus Bangalore 562112, Karnataka India
| | - Rangappa S. Keri
- Centre for Nano and Material SciencesJain University, Jain Global Campus Bangalore 562112, Karnataka India
| | - Gautam Achar
- Centre for Nano and Material SciencesJain University, Jain Global Campus Bangalore 562112, Karnataka India
| | - K. N. Brinda
- Centre for Nano and Material SciencesJain University, Jain Global Campus Bangalore 562112, Karnataka India
| |
Collapse
|
12
|
Milcendeau P, Sabat N, Ferry A, Guinchard X. Gold-catalyzed enantioselective functionalization of indoles. Org Biomol Chem 2020; 18:6006-6017. [DOI: 10.1039/d0ob01245a] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This review documents the potential of enantioselective gold catalysis for the functionalization of indoles.
Collapse
Affiliation(s)
- Pierre Milcendeau
- Université Paris-Saclay
- CNRS
- Institut de Chimie des Substances Naturelles
- UPR 2301
- Gif-sur-Yvette
| | - Nazarii Sabat
- Université Paris-Saclay
- CNRS
- Institut de Chimie des Substances Naturelles
- UPR 2301
- Gif-sur-Yvette
| | | | - Xavier Guinchard
- Université Paris-Saclay
- CNRS
- Institut de Chimie des Substances Naturelles
- UPR 2301
- Gif-sur-Yvette
| |
Collapse
|
13
|
Abstract
N-Heterocyclic carbenes have found many applications in modern metal catalysis, due to the formation of stable metal complexes, and organocatalysis. Among a myriad of N-heterocyclic carbene metal complexes, gold complexes have gained a lot of attention due to their unique propensity for the activation of carbon-carbon multiple bonds, allowing many useful transformations of alkynes, allenes, and alkenes, inaccessible by other metal complexes. The present review summarizes synthetic efforts towards the preparation of chiral N-heterocyclic gold(I) complexes exhibiting C2 and C1 symmetry, as well as their applications in enantioselective catalysis. Finally, the emerging area of rare gold(III) complexes and their preliminary usage in asymmetric catalysis is also presented.
Collapse
|
14
|
Zhang JQ, Liu Y, Wang XW, Zhang L. Synthesis of Chiral Bifunctional NHC Ligands and Survey of Their Utilities in Asymmetric Gold Catalysis. Organometallics 2019; 38:3931-3938. [PMID: 34290468 DOI: 10.1021/acs.organomet.9b00400] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis and characterization of the chiral bifunctional NHC ligands based on the imidazo[1,5-a]pyridine (ImPy) scaffold are described. These ligands possess a fluxional biaryl axis and a chiral center. The configurational stability of the biaryl axis in their gold(I) complexes is investigated. The application of these axially chiral ImPy-based AuCl complexes in a series of gold catalysis is explored, and varying degrees of asymmetric induction are observed. In most cases, the ligand (aS,R)-L8-H with its cyclohexyl group pointing to the reaction site and hence exerting asymmetric steric influence is more effective in asymmetric induction.
Collapse
Affiliation(s)
- Jun-Qi Zhang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Yunkui Liu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Xing-Wang Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Liming Zhang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| |
Collapse
|
15
|
Longhi A, Baron M, Rancan M, Bottaro G, Armelao L, Sgarbossa P, Tubaro C. Possible Synthetic Approaches for Heterobimetallic Complexes by Using nNHC/ tzNHC Heteroditopic Carbene Ligands. Molecules 2019; 24:E2305. [PMID: 31234368 PMCID: PMC6631958 DOI: 10.3390/molecules24122305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 11/21/2022] Open
Abstract
The synthesis of heterobimetallic complexes remains a synthetic challenge in the field of organometallic chemistry. A possible approach in this regard might be the use of a bidentate heteroditopic bis(carbene) ligand that combines an imidazol-2-ylidene (nNHC) with a 1,2,3-triazol-5-ylidene (tzNHC) connected by an organic spacer. The optimized strategy to heterobimetallic complexes with this type of ligand involves a 3-step procedure: (i) Coordination of the nNHC, functionalized with a 1,2,3-triazole ring, to a metal center; (ii) formation of the triazolium ring by alkylation of the triazole N-3; (iii) deprotonation of the tzNHC precursor and coordination of the second metal center. Following this procedure, a novel Au(I)-Ag(I) dinuclear complex was isolated and its properties were compared to the analogous homobimetallic Ag(I)-Ag(I) and Au(I)-Au(I) complexes. The study was completed by the determination of the molecular structures of some synthetic intermediates.
Collapse
Affiliation(s)
- Andrea Longhi
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.
| | - Marco Baron
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.
| | - Marzio Rancan
- Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council, ICMATE-CNR, c/o Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.
| | - Gregorio Bottaro
- Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council, ICMATE-CNR, c/o Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.
| | - Lidia Armelao
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.
- Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council, ICMATE-CNR, c/o Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.
| | - Paolo Sgarbossa
- Department of Industrial Engineering, University of Padova, via F. Marzolo 9, 35131 Padova, Italy.
| | - Cristina Tubaro
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.
| |
Collapse
|
16
|
Arai N, Ohkuma T. Stereoselective Construction of Methylenecyclobutane-Fused Indolines through Photosensitized [2+2] Cycloaddition of Allene-Tethered Indole Derivatives. Org Lett 2019; 21:1506-1510. [PMID: 30789275 DOI: 10.1021/acs.orglett.9b00309] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Irradiation of 1-(hexa-4,5-dienoyl)indole derivatives in the presence of an aromatic ketone by a high-pressure mercury lamp through Pyrex glass gave the corresponding cyclized products stereoselectively in high yields. The major part of the products was an all- cis-fused methylenecyclobutane-type compound produced through [2+2] cycloaddition, accompanied by small amounts of alkynes via 1,5-hydrogen transfer of a biradical intermediate. Among a range of aromatic ketones, 3',4'-dimethoxyacetophenone was found to sensitize the substrate quite effectively.
Collapse
Affiliation(s)
- Noriyoshi Arai
- Division of Applied Chemistry, Faculty of Engineering , Hokkaido University , Sapporo , Hokkaido 060-8628 , Japan
| | - Takeshi Ohkuma
- Division of Applied Chemistry, Faculty of Engineering , Hokkaido University , Sapporo , Hokkaido 060-8628 , Japan.,Frontier Chemistry Center, Faculty of Engineering , Hokkaido University , Sapporo , Hokkaido 060-8628 , Japan
| |
Collapse
|
17
|
Mascareñas JL, Varela I, López F. Allenes and Derivatives in Gold(I)- and Platinum(II)-Catalyzed Formal Cycloadditions. Acc Chem Res 2019; 52:465-479. [PMID: 30640446 PMCID: PMC6497370 DOI: 10.1021/acs.accounts.8b00567] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
![]()
Cycloaddition reactions, by involving the formation of at least
two bonds and one cycle in a single operation, represent one of the
more practical ways to assemble carbo- and heterocyclic structures
from simple acyclic precursors. Especially appealing are formal cycloadditions
promoted by transition metals, owing to the ability of these reagents
to open mechanisms that are not accessible using classical chemistry.
Therefore, along the years, a great variety of annulations based on
first-, and particularly second-row transition metals have been discovered.
Most of these reactions involve inner sphere mechanisms, with the
metal participating via standard oxidative addition or reductive elimination
processes. Curiously, metals of the third row like platinum and, especially,
gold remained largely unexplored, likely because of the belief that
they were inert and expensive. However, from the beginning of this
century, many groups realized that these metals can open very interesting
mechanistic scenarios and promote novel types of transformations.
In particular, the π-acidic, carbophilic behavior of gold(I)
complexes, together with the possibility of tuning their reactivity
using designed ligands, has triggered important activity in the field.
Many gold-catalyzed transformations involved addition or cycloisomerization
processes, but during recent years, there have been also important
advances in the development of formal cycloaddition reactions. While
many of these reactions rely on the activation of alkynes, there has
been an increasing number of reports that exploit the peculiar reactivities
of allenes and derivatives. In this Account, we present recent
efforts on the development of
platinum- and gold-catalyzed formal cycloadditions of allenes. For
the sake of simplicity, we only include annulations initiated by a
direct metal-promoted activation of the allene moiety. Thus, alternative
Pt- or Au-catalyzed reactions wherein the allene does not interact
with the metal catalyst are not covered. Upon activation by the metals,
allenes generate allyl-cation alkenylmetal species that can behave
as 1,2- or 1,3-carbon dipoles in cycloaddition processes. Especially
relevant is the reactivity of allenamides. The presence of the amide
substituent provides for the generation of gold intermediates with
a good balance of reactivity and stability, which can therefore react
with the corresponding partners in a controlled manner. Moreover,
despite the difficulties associated with the transfer of stereochemical
information from chiral linear gold(I) complexes, a variety of enantioselective
gold-catalyzed annulations have been discovered. This Account
is organized considering the number of atoms engaged
in the annulation process, and when possible, we present the results
in a chronological order.
Collapse
Affiliation(s)
- José L. Mascareñas
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Iván Varela
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Fernando López
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
- Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
| |
Collapse
|