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Abstract
The defining feature of the Nazarov cyclization is a 4π-conrotatory electrocyclization, resulting in the stereospecific formation of functionalized cyclopentanones. The reaction provides access to structural motifs that are found in many natural products and drug targets. Harnessing the full potential of the Nazarov cyclization broadens its utility by enabling the development of new methodologies and synthetic strategies. To achieve these goals through efficient cyclization design, it is helpful to think of the reaction as a two-stage process. The first stage involves a 4π-electrocyclization leading to the formation of an allylic cation, and the second stage corresponds to the fate of this cationic intermediate. With a complete understanding of the discrete events that characterize the overall process, one can optimize reactivity and control the selectivity of the different Stage 2 pathways.In this Account, we describe the development of methods that render the Nazarov cyclization catalytic and chemoselective, focusing specifically on advances made in our lab between 2002 and 2015. The initial discovery made in our lab involved reactions of electronically asymmetric ("polarized") substrates, which cyclize efficiently in the catalytic regime using mild Lewis acidic reagents. These cyclizations also exhibit selective eliminative behavior, increasing their synthetic utility. Research directed toward catalytic asymmetric Nazarov cyclization led to the serendipitous discovery of a 4π-cyclization coupled to a well-behaved Wagner-Meerwein rearrangement, representing an underexplored Stage 2 process. With careful choice of promoter and loading, it is possible to access either the rearrangement or the elimination pathway. Additional experimental and computational studies provided an effective model for anticipating the migratory behavior of substiutents in the rearrangements. Problem-solving efforts prompted investigation of alternative methods for generating pentadienyl cation intermediates, including oxidation of allenol ethers and addition of nucleophiles to dienyl diketones. These Nazarov cyclization variants afford cyclopentenone products with vicinal stereogenic centers and a different arrangement of substituents around the ring. A nucleophilic addition/cyclization/elimination sequence can be executed enantioselectively using catalytic amounts of a nonracemic chiral tertiary amine.In summary, the discovery and development of several new variations on the Nazarov electrocyclization are described, along with synthetic applications. This work illustrates how strongly substitution patterns can impact the efficiency of the 4π-electrocyclization (Stage 1), allowing for mild Lewis acid catalysis. Over the course of these studies, we have also identified new ways to access the critical pentadienyl cation intermediates and demonstrated strategies that exploit and control the different cationic pathways available post-electrocyclization (Stage 2 processes). These advances in Nazarov chemistry were subsequently employed in the synthesis of natural product targets such as (±)-merrilactone A, (±)-rocaglamide, and (±)-enokipodin B.
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Affiliation(s)
- Alison J. Frontier
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Jackson J. Hernandez
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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Mietke T, Cruchter T, Larionov VA, Faber T, Harms K, Meggers E. Asymmetric Nazarov Cyclizations Catalyzed by Chiral-at-Metal Complexes. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201701546] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Thomas Mietke
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Strasse 4 35043 Marburg Germany
| | - Thomas Cruchter
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Strasse 4 35043 Marburg Germany
| | - Vladimir A. Larionov
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Strasse 4 35043 Marburg Germany
- Department of Inorganic Chemistry; Peoples' Friendship University of Russia (RUDN University); Miklukho-Maklaya St. 6 117198 Moscow Russian Federation
| | - Tabea Faber
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Strasse 4 35043 Marburg Germany
| | - Klaus Harms
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Strasse 4 35043 Marburg Germany
| | - Eric Meggers
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Strasse 4 35043 Marburg Germany
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Hoffmann M, Miaskiewicz S, Weibel JM, Pale P, Blanc A. Assigning regioisomeric or diastereoisomeric relations of problematic trisubstituted double-bonds through heteronuclear 2D selective J-resolved NMR spectroscopy. RSC Adv 2015. [DOI: 10.1039/c5ra03228h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although one of the first 2D NMR methods, but so far neglected, selectiveJ-resolved NMR spectroscopy offers a unique opportunity to help organic chemists in structure elucidation, avoiding natural and non-natural product misassignments.
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Affiliation(s)
- Marie Hoffmann
- Laboratoire de Synthèse
- Réactivité Organiques et Catalyse
- UMR 7177 associé au CNRS
- Institut de Chimie
- Université de Strasbourg
| | - Solène Miaskiewicz
- Laboratoire de Synthèse
- Réactivité Organiques et Catalyse
- UMR 7177 associé au CNRS
- Institut de Chimie
- Université de Strasbourg
| | - Jean-Marc Weibel
- Laboratoire de Synthèse
- Réactivité Organiques et Catalyse
- UMR 7177 associé au CNRS
- Institut de Chimie
- Université de Strasbourg
| | - Patrick Pale
- Laboratoire de Synthèse
- Réactivité Organiques et Catalyse
- UMR 7177 associé au CNRS
- Institut de Chimie
- Université de Strasbourg
| | - Aurélien Blanc
- Laboratoire de Synthèse
- Réactivité Organiques et Catalyse
- UMR 7177 associé au CNRS
- Institut de Chimie
- Université de Strasbourg
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Vaidya T, Cheng R, Carlsen PN, Frontier AJ, Eisenberg R. Cationic cyclizations and rearrangements promoted by a heterogeneous gold catalyst. Org Lett 2014; 16:800-3. [PMID: 24432741 PMCID: PMC3969096 DOI: 10.1021/ol403542k] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Indexed: 12/02/2022]
Abstract
A heterogeneous gold catalyst with remarkable activity for promoting the electrophilic reactions of aryl vinyl ketones and aryl dienyl ketones is described. The catalyst is easy to prepare, is robust, and can be recycled. Low loadings are effective for different types of cationic reactions, including Nazarov cyclizations, lactonizations, and [1,2] shifts.
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Affiliation(s)
- Tulaza Vaidya
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
| | - Ryan Cheng
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
| | - Peter N. Carlsen
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
| | - Alison J. Frontier
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
| | - Richard Eisenberg
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
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Lebœuf D, Gandon V, Ciesielski J, Frontier AJ. Experimental and theoretical studies on the Nazarov cyclization/Wagner-Meerwein rearrangement sequence. J Am Chem Soc 2012; 134:6296-308. [PMID: 22471833 PMCID: PMC3382077 DOI: 10.1021/ja211970p] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Highly functionalized cyclopentenones can be generated by a chemoselective copper(II)-mediated Nazarov/Wagner-Meerwein rearrangement sequence of divinyl ketones. A detailed investigation of this sequence is described including a study of substrate scope and limitations. After the initial 4π electrocyclization, this reaction proceeds via two different sequential [1,2]-shifts, with selectivity that depends upon either migratory ability or the steric bulkiness of the substituents at C1 and C5. This methodology allows the creation of vicinal stereogenic centers, including adjacent quaternary centers. This sequence can also be achieved by using a catalytic amount of copper(II) in combination with NaBAr(4)(f), a weak Lewis acid. During the study of the scope of the reaction, a partial or complete E/Z isomerization of the enone moiety was observed in some cases prior to the cyclization, which resulted in a mixture of diastereomeric products. Use of a Cu(II)-bisoxazoline complex prevented the isomerization, allowing high diastereoselectivity to be obtained in all substrate types. In addition, the reaction sequence was studied by DFT computations at the UB3LYP/6-31G(d,p) level, which are consistent with the proposed sequences observed, including E/Z isomerizations and chemoselective Wagner-Meerwein shifts.
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Affiliation(s)
- David Lebœuf
- Department of Chemistry, University of Rochester, Rochester, NY 14627
| | - Vincent Gandon
- ICMMO, UMR CNRS 8182, Université Paris-Sud 11, 91405 Orsay cedex, France
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Schotes C, Mezzetti A. Alkylidene β-Ketoesters in Asymmetric Catalysis: Recent Developments. ACS Catal 2012. [DOI: 10.1021/cs300035m] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christoph Schotes
- Department of Chemistry and Applied
Biosciences, ETH Zürich, CH-8093
Zürich, Switzerland
| | - Antonio Mezzetti
- Department of Chemistry and Applied
Biosciences, ETH Zürich, CH-8093
Zürich, Switzerland
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Schotes C, Althaus M, Aardoom R, Mezzetti A. Asymmetric Diels-Alder and Ficini reactions with alkylidene β-ketoesters catalyzed by chiral ruthenium PNNP complexes: mechanistic insight. J Am Chem Soc 2012; 134:1331-43. [PMID: 22191539 DOI: 10.1021/ja210372u] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydride abstraction from the β-position of the enolato ligand of the previously reported complex [Ru(3a-H)(PNNP)]PF(6) (5a; 3a-H is the enolate of 2-tert-butoxycarbonylcyclopentanone) with (Ph(3)C)PF(6) gives the dicationic complex [Ru(6a)(PNNP)](2+) (7a) as a single diastereoisomer, which contains the unsaturated β-ketoester 2-tert-butoxycarbonyl-2-cyclopenten-1-one (6a) as a chelating ligand. The methyl analogue 2-methoxycarbonylcyclopentanone (3b) gives [Ru(3b-H)(PNNP)]PF(6) as a mixture of noninterconverting diastereoisomers (ester group of 3b trans to P, 5b; or to N, 5c), which were separated by column chromatography. Hydride abstraction from 5b (or 5c) yields diastereomerically pure [Ru(6b)(PNNP)](2+) (7b or 7c). Complexes 7b and 7c do not interconvert at room temperature in CD(2)Cl(2) and form opposite enantiomers of the Diels-Alder adduct upon reaction with Dane's diene (1 equiv). X-ray studies of 7a, 5b, and 5c give insight into the origin of enantioselection and the sense of asymmetric induction in the previously reported asymmetric Diels-Alder and Ficini cycloaddition reactions with 2,3-disubstituted butadienes and ynamides, respectively. Stoichiometric reactions (substrate coordination, cycloaddition, and product displacement) between [Ru(OEt(2))(2)(PNNP)](2+) (2), 6b (or 6a), and Dane's diene (15, to give estrone derivatives) or N-benzyl-N-(cyclohexylethynyl)-4-methylbenzenesulfonamide (17, to give cyclobutenamides) suggest that product displacement from the catalyst is turnover limiting.
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Affiliation(s)
- Christoph Schotes
- Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
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Chiaradia LD, Martins PGA, Cordeiro MNS, Guido RVC, Ecco G, Andricopulo AD, Yunes RA, Vernal J, Nunes RJ, Terenzi H. Synthesis, biological evaluation, and molecular modeling of chalcone derivatives as potent inhibitors of Mycobacterium tuberculosis protein tyrosine phosphatases (PtpA and PtpB). J Med Chem 2011; 55:390-402. [PMID: 22136336 DOI: 10.1021/jm2012062] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tuberculosis (TB) is a major infectious disease caused by Mycobacterium tuberculosis (Mtb). According to the World Health Organization (WHO), about 1.8 million people die from TB and 10 million new cases are recorded each year. Recently, a new series of naphthylchalcones has been identified as inhibitors of Mtb protein tyrosine phosphatases (PTPs). In this work, 100 chalcones were designed, synthesized, and investigated for their inhibitory properties against MtbPtps. Structure-activity relationships (SAR) were developed, leading to the discovery of new potent inhibitors with IC(50) values in the low-micromolar range. Kinetic studies revealed competitive inhibition and high selectivity toward the Mtb enzymes. Molecular modeling investigations were carried out with the aim of revealing the most relevant structural requirements underlying the binding affinity and selectivity of this series of inhibitors as potential anti-TB drugs.
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Affiliation(s)
- Louise Domeneghini Chiaradia
- Centro de Biologia Molecular Estrutural, CEBIME-UFSC, Universidade Federal de Santa Catarina, Campus Trindade, 88040-900 Florianópolis-SC, Brasil
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Lebœuf D, Huang J, Gandon V, Frontier AJ. Using Nazarov electrocyclization to stage chemoselective [1,2]-migrations: stereoselective synthesis of functionalized cyclopentenones. Angew Chem Int Ed Engl 2011; 50:10981-5. [PMID: 21953873 DOI: 10.1002/anie.201104870] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 08/17/2011] [Indexed: 11/08/2022]
Affiliation(s)
- David Lebœuf
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
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10
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Marosvölgyi-Haskó D, Petz A, Takács A, Kollár L. Synthesis of tetrahydrophthalazine and phthalamide (phthalimide) derivatives via palladium-catalysed carbonylation of iodoarenes. Tetrahedron 2011. [DOI: 10.1016/j.tet.2011.09.095] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Sano S, Okubo Y, Handa A, Nakao M, Kitaike S, Nagao Y, Kakegawa H. Reinvestigation of the synthesis of isoliquiritigenin: application of Horner-Wadsworth-Emmons reaction and Claisen-Schmidt condensation. Chem Pharm Bull (Tokyo) 2011; 59:885-8. [PMID: 21720042 DOI: 10.1248/cpb.59.885] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isoliquiritigenin [ILG, (E)-1] was readily prepared via the Horner-Wadsworth-Emmons reactions using β-ketophosphonates 5a, b. An improved protocol for the synthesis of (E)-1 via the Claisen-Schmidt condensation was also presented.
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Affiliation(s)
- Shigeki Sano
- Graduate School of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Japan.
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Lebœuf D, Huang J, Gandon V, Frontier AJ. Using Nazarov Electrocyclization to Stage Chemoselective [1,2]-Migrations: Stereoselective Synthesis of Functionalized Cyclopentenones. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201104870] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Huang J, Lebœuf D, Frontier AJ. Understanding the fate of the oxyallyl cation following Nazarov electrocyclization: sequential Wagner-Meerwein migrations and the synthesis of spirocyclic cyclopentenones. J Am Chem Soc 2011; 133:6307-17. [PMID: 21466152 DOI: 10.1021/ja111504w] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A general reaction sequence is described that involves Nazarov cyclization followed by two sequential Wagner-Meerwein migrations, to afford spirocyclic compounds from divinyl ketones in the presence of 1 equiv of copper(II) complexes. A detailed investigation of this sequence is described including a study of substrate scope and limitations. It was found that after 4π electrocyclization, two different pathways are available to the oxyallyl cation intermediate: elimination of a proton can give the usual Nazarov cycloadduct, or ring contraction can give an alternative tertiary carbocation. After ring contraction, either [1,2]-hydride or carbon migration can occur, depending upon the substitution pattern of the substrate, to furnish spirocyclic products. The rearrangement pathway is favored over the elimination pathway when catalyst loading is high and the copper(II) counterion is noncoordinating. Several ligands were found to be effective for the reaction. Thus, the reaction sequence can be controlled by judicious choice of reaction conditions to allow selective generation of richly functionalized spirocycles. The three steps of the sequence are stereospecific: electrocyclization followed by two [1,2]-suprafacial Wagner-Meerwein shifts, the ring contraction and then a hydride, alkenyl, or aryl shift. The method allows stereospecific installation of adjacent stereocenters or adjacent quaternary centers arrayed around a cyclopentenone ring.
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Affiliation(s)
- Jie Huang
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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15
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Vaidya T, Manbeck GF, Chen S, Frontier AJ, Eisenberg R. Divergent reaction pathways of a cationic intermediate: rearrangement and cyclization of 2-substituted furyl and benzofuryl enones catalyzed by iridium(III). J Am Chem Soc 2011; 133:3300-3. [PMID: 21322633 DOI: 10.1021/ja111317q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In contrast to 2-substituted pyrrole enones, furyl and benzofuryl enones do not undergo the Nazarov electrocyclization. Instead, these furyl and benzofuryl enones exhibit unusual rearrangement sequences in the presence of catalytic amounts of [IrBr(CO)(DIM)((R)-(+)-BINAP)](SbF(6))(2) (1; DIM = diethylisopropylidene malonate) and AgSbF(6) (1:1). A 1,2-H shift followed by intramolecular Friedel-Crafts alkylation leads to synthetically valuable cyclohexanones with furanylic quaternary centers. The electrophilicity of 1 is essential for this rearrangement.
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Affiliation(s)
- Tulaza Vaidya
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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Zhang J, Vaidya T, Brennessel WW, Frontier AJ, Eisenberg R. Dicationic Palladium(II) Complexes as Active Lewis Acid Catalysts for Polarized Nazarov Cyclization. Organometallics 2010. [DOI: 10.1021/om100274g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jing Zhang
- Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Tulaza Vaidya
- Department of Chemistry, University of Rochester, Rochester, New York 14627
| | | | - Alison J. Frontier
- Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Richard Eisenberg
- Department of Chemistry, University of Rochester, Rochester, New York 14627
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Vaidya T, Atesin AC, Herrick IR, Frontier AJ, Eisenberg R. A highly reactive dicationic iridium(III) catalyst for the polarized Nazarov cyclization reaction. Angew Chem Int Ed Engl 2010; 49:3363-6. [PMID: 20358570 PMCID: PMC3032601 DOI: 10.1002/anie.201000100] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pushing the Nazarov Envelope A new electrophilic complex [IrBr(CO)(diethylisopropylidene malonate)((R )-(+)-BINAP)](SbF6)2 (2 ) exhibits unusual activity in the catalysis of polarized Nazarov cyclization. Aryl vinyl ketones that show poor reactivity with well-known catalysts such as [Ir(CH3)(CO)(1,2-diiodobenzene)(dppe)](B(Arf)4−)2 (1 ), Sc(OTf)3 + LiClO4 and Cu(ClO4)2, can be cyclized with 2 + AgSbF6 (1:1) under mild conditions with concurrent AgBr precipitation.
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Affiliation(s)
- Tulaza Vaidya
- Department of Chemistry, University of Rochester, Rochester, New York 14627 (USA)
| | | | - Ildiko R. Herrick
- Department of Chemistry, University of Rochester, Rochester, New York 14627 (USA)
| | - Alison J. Frontier
- Department of Chemistry, University of Rochester, Rochester, New York 14627 (USA)
| | - Richard Eisenberg
- Department of Chemistry, University of Rochester, Rochester, New York 14627 (USA)
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18
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Atesin AC, Zhang J, Vaidya T, Brennessel WW, Frontier AJ, Eisenberg R. Synthesis, Characterization, and Catalytic Properties of New Electrophilic Iridium(III) Complexes Containing the (R)-(+)-2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl Ligand. Inorg Chem 2010; 49:4331-42. [DOI: 10.1021/ic100300y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Abdurrahman C Atesin
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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19
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Vaidya T, Atesin A, Herrick I, Frontier A, Eisenberg R. A Highly Reactive Dicationic Iridium(III) Catalyst for the Polarized Nazarov Cyclization Reaction. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201000100] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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G. Occhiato E, Prandi C, Scarpi D. Carbonylative Palladium-Catalyzed Reactions of Lactam-, Lactone-, and Thiolactone-Derived Vinyl Triflates and Phosphates for the Synthesis of N-, O-, and S-Heterocycles. HETEROCYCLES 2010. [DOI: 10.3987/rev-09-sr(s)5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Bolaño T, Castarlenas R, Esteruelas MA, Oñate E. Nazarov type cyclization on an osmium-dienylcarbene complex. J Am Chem Soc 2009; 131:2064-5. [PMID: 19161302 DOI: 10.1021/ja8093058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Nazarov reaction is an acid-catalyzed 4pi-electrocyclic ring closure of dienylketones, which affords cyclopentenones. This type of cyclization has been increasing in interest over the years, due to the importance of the construction of five-membered rings in the synthesis of natural products. However, one potential problem is that the carbonyl group necessary for the cyclization to occur may not be required in the final synthetic target and can sometimes be difficult to remove or modify. One possible solution is to design analogous reactions which do not suffer the carbonyl dependence.
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Affiliation(s)
- Tamara Bolaño
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
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Grant TN, Rieder CJ, West FG. Interrupting the Nazarov reaction: domino and cascade processes utilizing cyclopentenyl cations. Chem Commun (Camb) 2009:5676-88. [PMID: 19774236 DOI: 10.1039/b908515g] [Citation(s) in RCA: 226] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Tina N Grant
- Department of Chemistry, Faculty of Science, E3-43 Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2
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Cavalli A, Pacetti A, Recanatini M, Prandi C, Scarpi D, Occhiato E. Predicting Reactivity and Stereoselectivity in the Nazarov Reaction: A Combined Computational and Experimental Study. Chemistry 2008; 14:9292-304. [DOI: 10.1002/chem.200801030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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He W, Herrick IR, Atesin TA, Caruana PA, Kellenberger CA, Frontier AJ. Polarizing the Nazarov cyclization: the impact of dienone substitution pattern on reactivity and selectivity. J Am Chem Soc 2008; 130:1003-11. [PMID: 18161974 DOI: 10.1021/ja077162g] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The impact of dienone substitution on the Nazarov cyclization has been examined in detail. Substrates bearing different substituents at each of four positions on the dienone backbone were systematically probed in order to identify trends leading to higher reactivity and better selectivity. Desymmetrization of the pentadienyl cation and oxyallyl cation intermediates through placement of polarizing groups at both the C-2 and C-4 positions was found to be particularly effective. These modifications allowed cyclizations to occur in the presence of catalytic amounts of mild Lewis acids. It was also found that stereoconvergent cyclization of mixtures of E and Z isomers of alkylidene beta-ketoesters occurred via an efficient isomerization process that occurred under the reaction conditions.
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Affiliation(s)
- Wei He
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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25
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Affiliation(s)
- Wei He
- Contribution from the Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Jie Huang
- Contribution from the Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Xiufeng Sun
- Contribution from the Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Alison J. Frontier
- Contribution from the Department of Chemistry, University of Rochester, Rochester, New York 14627
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Generation of Ir–Sn and Rh–Sn bonds from the oxidative addition of tin(IV) halides to [Ir(μ-Cl)(1,5-COD)]2 and [Rh(μ-Cl)(1,5-COD)]2. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2007.09.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Janka M, He W, Haedicke IE, Fronczek FR, Frontier AJ, Eisenberg R. Tandem Nazarov cyclization-michael addition sequence catalyzed by an Ir(III) complex. J Am Chem Soc 2007; 128:5312-3. [PMID: 16620081 DOI: 10.1021/ja058772o] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first examples of a tandem Nazarov cyclization/Michael addition process are described. The sequence is efficiently catalyzed by Ir[Me(CO)(dppe)(DIB)]2+ and occurs with high diastereoselectivity, creating three contiguous stereocenters. The mechanistic factors controlling the reactivity and diastereoselectivity are discussed.
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Affiliation(s)
- Mesfin Janka
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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Walz I, Bertogg A, Togni A. Cationic Vanadium(IV) Complexes as Efficient Catalysts for Nazarov Cyclizations. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700156] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bartali L, Guarna A, Larini P, Occhiato EG. Carbonylative Suzuki–Miyaura Coupling Reaction of Lactam-, Lactone-, and Thiolactone-Derived Enol Triflates for the Synthesis of Unsymmetrical Dienones. European J Org Chem 2007. [DOI: 10.1002/ejoc.200601089] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Malona JA, Colbourne JM, Frontier AJ. A General Method for the Catalytic Nazarov Cyclization of Heteroaromatic Compounds. Org Lett 2006; 8:5661-4. [PMID: 17107097 DOI: 10.1021/ol062403v] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A general, catalytic method for efficient Nazarov cyclization of systems containing heteroaromatic components has been developed. Scandium triflate was identified as the most reactive promoter, and it was found that addition of lithium perchlorate was necessary for synthetically useful catalytic cyclizations. The method was used to synthesize a range of cyclopentanone-fused heteroaromatic systems in 36-97% yield, and the reactivity trends observed demonstrate the impact of polarization on cyclization efficiency. [reaction: see text].
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Affiliation(s)
- John A Malona
- Department of Chemistry, University of Rochester, Rochester, New York, 14627, USA
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Janka M, Atesin AC, Fox DJ, Flaschenriem C, Brennessel WW, Eisenberg R. Highly Diastereoselective Oxidative Addition of Methyl Iodide to a Chiral Square-Planar Complex. Inorg Chem 2006; 45:6559-61. [PMID: 16903699 DOI: 10.1021/ic052027v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxidative addition of methyl iodide to the chiral square-planar complex IrI(CO)(duphos) shows a high level of diastereoselectivity. The basis for the diastereoselectivity of the reaction is best explained based on the crystal structure of IrI(CO)(duphos) in which methyl iodide approach across the two faces is differentiated by the chiral ligand.
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Affiliation(s)
- Mesfin Janka
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
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Larini P, Guarna A, Occhiato EG. The Lewis Acid-Catalyzed Nazarov Reaction of 2-(N-Methoxycarbonylamino)-1,4-pentadien-3-ones. Org Lett 2006; 8:781-4. [PMID: 16468766 DOI: 10.1021/ol053071h] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] A highly efficient carbonylative Suzuki-Miyaura coupling reaction of lactam-derived vinyl triflates and alkenylboronic acids afforded 2-(N-methoxycarbonylamino)-1,4-pentadien-3-ones as suitable substrates for the Nazarov reaction. The most competent Lewis acids for the Nazarov reaction were Cu(OTf)(2) (2 mol %) and Sc(OTf)(3) (3 mol %) in DCE, which provided the Nazarov products in excellent yield. As both the carbonylative coupling and the subsequent Nazarov reaction were high yielding, the overall methodology is a concise and efficient route to [1]pyrindine systems.
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Affiliation(s)
- Paolo Larini
- Dipartimento di Chimica Organica U. Schiff, Università di Firenze, Via della Lastruccia 13, I-50019 Sesto Fiorentino, Italy
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