1
|
Maya Pai M, Yallur BC, Batakurki SR, Adimule V. Synthesis and Catalytic Activity of Heterogenous Hybrid Nanocatalyst of Copper/Palladium MOF, RIT 62-Cu/Pd for Stille Polycondensation of Thieno[2,3-b]pyrrol-5-One Derivatives. Top Catal 2022. [DOI: 10.1007/s11244-022-01618-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
2
|
Rullah K, Mohd Aluwi MFF, Yamin BM, Juan JC, Wai LK. Palladium‐Catalysed Cross‐Coupling Reactions for the Synthesis of Chalcones. ASIAN J ORG CHEM 2019. [DOI: 10.1002/ajoc.201900297] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Kamal Rullah
- Department of Pharmaceutical Chemistry Kulliyyah of PharmacyInternational Islamic University Malaysia Bandar Indera Mahkota 25200 Kuantan, Pahang Malaysia
- Drugs and Herbal Research Centre Faculty of PharmacyUniversiti Kebangsaan Malaysia Jalan Raja Muda Abdul Aziz 50300 Kuala Lumpur Malaysia
- Nanotechnology and Catalysis Research Centre (NANOCAT)University of Malaya 50603 Kuala Lumpur Malaysia
| | | | - Bohari M. Yamin
- School of Chemical Sciences & Food TechnologyUniversiti Kebangsaan Malaysia 43600 Bangi, Selangor Malaysia
| | - Joon Ching Juan
- Nanotechnology and Catalysis Research Centre (NANOCAT)University of Malaya 50603 Kuala Lumpur Malaysia
| | - Lam Kok Wai
- Drugs and Herbal Research Centre Faculty of PharmacyUniversiti Kebangsaan Malaysia Jalan Raja Muda Abdul Aziz 50300 Kuala Lumpur Malaysia
| |
Collapse
|
3
|
Volpe R, Lepage RJ, White JM, Krenske EH, Flynn BL. Asymmetric synthesis of multiple quaternary stereocentre-containing cyclopentyls by oxazolidinone-promoted Nazarov cyclizations. Chem Sci 2018; 9:4644-4649. [PMID: 29899958 PMCID: PMC5969496 DOI: 10.1039/c8sc00031j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/19/2018] [Indexed: 01/29/2023] Open
Abstract
Carbometalation of oxazolidinone (Ox)-substituted ynamides is used to generate highly substituted Ox-divinyl (and aryl vinyl) ketones for use in Nazarov cyclizations. The Ox-group serves as a remarkably effective chiral activating group, enabling the torquoselective Nazarov cyclization of these sterically congested substrates to be performed under mild conditions. It also serves as a charge-stabilizing group in the intermediate oxyallyl cation, suppressing undesired [1,2]-sigmatropic shifts of neighboring substituents and facilitating the regio- and stereoselective incorporation of nucleophiles to yield cyclopentanoids containing up to three contiguous all-carbon quaternary (4°) stereocentres.
Collapse
Affiliation(s)
- Rohan Volpe
- Monash Institute of Pharmaceutical Sciences , Monash University , 381 Royal Parade , Parkville , Victoria 3052 , Australia .
| | - Romain J Lepage
- School of Chemistry and Molecular Biosciences , The University of Queensland , Brisbane , QLD 4072 , Australia
| | - Jonathan M White
- Bio21 Institute , School of Chemistry , University of Melbourne , Parkville , VIC 3010 , Australia
| | - Elizabeth H Krenske
- School of Chemistry and Molecular Biosciences , The University of Queensland , Brisbane , QLD 4072 , Australia
| | - Bernard L Flynn
- Monash Institute of Pharmaceutical Sciences , Monash University , 381 Royal Parade , Parkville , Victoria 3052 , Australia .
| |
Collapse
|
4
|
Manchala N, Law HYL, Kerr DJ, Volpe R, Lepage RJ, White JM, Krenske EH, Flynn BL. Multistereocenter-Containing Cyclopentanoids from Ynamides via Oxazolidinone-Controlled Nazarov Cyclization. J Org Chem 2017; 82:6511-6527. [PMID: 28511015 DOI: 10.1021/acs.joc.7b00082] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Achieving ready-enantioselective access to multistereocenter-containing cyclopentyl rings is an area of great significance to organic synthesis. In this work, we describe a general protocol for accessing multistereocenter-containing cyclopentanoids from simple N-alkynyloxazolidinones (Ox-ynamides). This protocol involves conversion of Ox-ynamides into Ox-activated divinyl and aryl vinyl ketones that undergo facile Nazarov cyclization with excellent chemo-, regio-, and stereocontrol. The Ox auxiliary directs all aspects of reactivity and selectivity, both in the electrocyclization and in the subsequent transformations of the resulting oxyallyl intermediate. Stereoinduction in the electrocyclization results from a "coupled-torque" mechanism in which rotation of the Ox group, driven by increasing orbital overlap of the nitrogen lone pair with the incipient oxyallyl cation, is coupled with the rotation of the termini of the pentadienyl cation, favoring a particular direction of conrotatory ring closure (torquoselectivity). The associated lone-pair stabilization of the transition state by Ox promotes cyclization of traditionally resistant substrates, broadening the scope of this asymmetric Nazarov cyclization. The Ox group also facilitates the stereo- and regioselective incorporation of nucleophiles (Nu) and dienes, giving more complex, multistereocenter containing cyclopentanoids. Finally, the Ox group is readily removed and recovered or can be converted into other amine functionalities.
Collapse
Affiliation(s)
- Narasimhulu Manchala
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Hanson Y L Law
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Daniel J Kerr
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Rohan Volpe
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Romain J Lepage
- School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Jonathan M White
- Bio21 Institute, School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Elizabeth H Krenske
- School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Bernard L Flynn
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| |
Collapse
|
5
|
Concise and direct construction of cis-pyrano[4,3-b]pyran-5-one skeleton from glucal derivatives: synthesis of ent-4-deoxy-2,3-di-epi-dinemasone BC. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.07.055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
6
|
Larsen MH, Nielsen MB. The Gilded Edge in Acetylenic Scaffolding II: A Computational Study of the Transmetalation Processes Involved in Palladium-Catalyzed Cross-Couplings of Gold(I) Acetylides. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mie Højer Larsen
- Center for Exploitation of
Solar Energy, Department of Chemistry, University of Copenhagen, Universitetsparken
5, DK-2100 Copenhagen
Ø, Denmark
| | - Mogens Brøndsted Nielsen
- Center for Exploitation of
Solar Energy, Department of Chemistry, University of Copenhagen, Universitetsparken
5, DK-2100 Copenhagen
Ø, Denmark
| |
Collapse
|
7
|
Yano H, Nakajima Y, Obora Y. N,N-Dimethylformamide-stabilized palladium nanoclusters as catalyst for Migita–Kosugi–Stille cross-coupling reactions. J Organomet Chem 2013. [DOI: 10.1016/j.jorganchem.2013.08.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
8
|
Joy S, Nakanishi W, West F. Hydroxylic additives enhance yield and scalability of silicon-directed Nazarov reaction. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.07.139] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
9
|
delPozo J, Carrasco D, Pérez-Temprano MH, García-Melchor M, Álvarez R, Casares JA, Espinet P. Stille Coupling Involving Bulky Groups Feasible with Gold Cocatalyst. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201209262] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
10
|
delPozo J, Carrasco D, Pérez-Temprano MH, García-Melchor M, Álvarez R, Casares JA, Espinet P. Stille coupling involving bulky groups feasible with gold cocatalyst. Angew Chem Int Ed Engl 2013; 52:2189-93. [PMID: 23341137 DOI: 10.1002/anie.201209262] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Indexed: 11/12/2022]
Affiliation(s)
- Juan delPozo
- Química Inorgánica, I. U. CINQUIMA, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid, Spain
| | | | | | | | | | | | | |
Collapse
|
11
|
Bahari S, Mohammadi-Aghdam B, Molaei R, Gharibi Z. Diphenylphosphinoethane-functionalized polystyrene resin-supported Pd(0) complex — A highly active and recyclable catalyst for the Stille reaction under aerobic conditions. CAN J CHEM 2012. [DOI: 10.1139/v2012-044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The polymer-supported palladium(II) diphenylphosphinoethane complex is a highly active catalyst that could be used for the Stille coupling reaction between aryl iodides and (or) chlorides and organostannanes at room temperature under aerobic conditions. This heterogeneous palladium catalyst is efficient, air-stable, and recyclable.
Collapse
Affiliation(s)
- Siavash Bahari
- Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran
| | | | - Rahim Molaei
- Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran
- Department of Chemistry, Faculty of Science, Urmia University, Urmia, Iran
| | - Zakiyeh Gharibi
- Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran
| |
Collapse
|
12
|
Kerr DJ, Miletic M, Chaplin JH, White JM, Flynn BL. Oxazolidinone-promoted, torquoselective Nazarov cyclizations. Org Lett 2012; 14:1732-5. [PMID: 22455473 DOI: 10.1021/ol300316a] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxazolidinones are powerful promoters of the Nazarov reaction, enabling the cyclization of conventionally resistant substrates to be achieved under mild conditions. They exert excellent regio- and torquoselective control in both the conventional Nazarov reaction giving cyclopentenones and in the "interrupted" Nazarov reaction, giving more highly substituted multistereocenter containing products.
Collapse
Affiliation(s)
- Daniel J Kerr
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | | | | | | | | |
Collapse
|
13
|
Wu YK, Niu T, West FG. Construction of α-amido-indanones via formal allenamide hydroacylation–Nazarov cyclization. Chem Commun (Camb) 2012; 48:9186-8. [DOI: 10.1039/c2cc34644c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
14
|
Wu XF, Neumann H, Beller M. Palladium-catalyzed carbonylative coupling reactions between Ar–X and carbon nucleophiles. Chem Soc Rev 2011; 40:4986-5009. [DOI: 10.1039/c1cs15109f] [Citation(s) in RCA: 766] [Impact Index Per Article: 58.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
15
|
Peng Y, Li WZ. cine
Substitution and the Cu Effect in Stille Cross‐Coupling Reactions: Mechanistic Perspectives and Synthetic Utility. European J Org Chem 2010. [DOI: 10.1002/ejoc.201000557] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yu Peng
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
| | - Wei‐Dong Z. Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
- State Key Laboratory of Elemento‐organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. China, Fax: +86‐22‐23494613
| |
Collapse
|
16
|
Pal A, Ghosh R, Adarsh N, Sarkar A. Pyrazole-tethered phosphine ligands for Pd(0): useful catalysts for Stille, Kumada and Hiyama cross-coupling reactions. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.05.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
17
|
Canterbury DP, Herrick IR, Um J, Houk KN, Frontier AJ. A Torquoselective Extrusion of Isoxazoline N-Oxides. Application to the Synthesis of Aryl Vinyl and Divinyl Ketones for Nazarov Cyclization. Tetrahedron 2009; 65:3165-3179. [PMID: 20161228 PMCID: PMC2703503 DOI: 10.1016/j.tet.2008.10.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A mild, convenient reaction sequence for the synthesis of Nazarov cyclization substrates is described. The [3+2] dipolar cycloaddition of a nitrone and an electron-deficient alkyne gives an isolable isoxazoline intermediate, which upon oxidation undergoes stereoselective extrusion of nitrosomethane to give aryl vinyl or divinyl ketones.
Collapse
Affiliation(s)
- Daniel P Canterbury
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | | | | | | | | |
Collapse
|
18
|
González-Nogal AM, Cuadrado P, Sarmentero MA. Regio- and Stereospecific Cleavage of Stannyloxiranes with Lithium Diphenylphosphide. European J Org Chem 2009. [DOI: 10.1002/ejoc.200800984] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
19
|
Fürstner A, Funel JA, Tremblay M, Bouchez LC, Nevado C, Waser M, Ackerstaff J, Stimson CC. A versatile protocol for Stille–Migita cross coupling reactions. Chem Commun (Camb) 2008:2873-5. [DOI: 10.1039/b805299a] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
20
|
Benson CL, West FG. Highly Stereoselective 6π Electrocyclization of Bridged Bicyclic 1,3,5-Trienes. Org Lett 2007; 9:2545-8. [PMID: 17530764 DOI: 10.1021/ol070924s] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conjugated 1,3,5-hexatrienes encased in bridged bicyclic skeletons are prepared by cross-coupling followed by half-reduction of the resulting dienynes. The trienes undergo 6pi electrocyclization at an ambient or elevated temperature to furnish complex, polycyclic cyclohexadienes. In all cases, complete selectivity in favor of cyclization from the exo face of the bridged bicyclic system was seen, in contrast to the corresponding 4pi Nazarov cyclizations.
Collapse
Affiliation(s)
- Chantel L Benson
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | | |
Collapse
|
21
|
|
22
|
Mei X, Martin RM, Wolf C. Synthesis of a Sterically Crowded Atropisomeric 1,8-Diacridylnaphthalene for Dual-Mode Enantioselective Fluorosensing. J Org Chem 2006; 71:2854-61. [PMID: 16555842 DOI: 10.1021/jo0600353] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An efficient synthetic route to a sterically crowded 1,8-diheteroarylnaphthalene-derived enantioselective fluorosensor that operates in two different detection modes utilizing fluorescence lifetime and intensity has been developed. Screening of palladium-catalyzed Negishi, Kumada, Suzuki, Hiyama, and Stille coupling methods showed that the latter affords highly congested 1,8-diarylnaphthalenes in superior yields. Despite severe steric hindrance, axially chiral 1,8-bis(3-(3',5'-dimethylphenyl)-9-acridyl)naphthalene, 1, was obtained in 68% yield from 1,8-dibromonaphthalene, 14, and 3-(3',5'-dimethylphenyl)-9-tributylstannylacridine, 13, via two consecutive Stille cross-coupling steps using tetrakis(triphenylphosphine)palladium(0) as catalyst in the presence of copper(II) oxide. The preparation of 1 involved formation of 4-(3',5'-dimethylphenyl)-2-chlorobenzoic acid, 7, through microwave-assisted Suzuki coupling of 4-bromo-2-chlorobenzoic acid, 10, and 3,5-dimethylphenylboronic acid, 11, followed by regioselective amination with aniline and acridine ring construction in phosphorus oxybromide. Lithiation, subsequent treatment with trimethylstannyl chloride, and Stille cross-coupling then completed the five-reaction sequence providing 1 in 57% overall yield. The enantiomers of 1 were separated by semipreparative HPLC on a (R,R)-Whelk-O 1 column and successfully employed in enantioselective fluorosensing of N-t-Boc-protected serine, 20, glutamine, 22, proline, 23, and 2-hydoxy-2-methylsuccinic acid, 21. Fluorescence titration experiments with 23 revealed that both static and dynamic quenching occur with distinctive enantioselectivity. Addition of (R)-23 to a solution of (+)-1 in acetonitrile resulted in stronger fluorescence quenching than titration with the (S)-enantiomer of 23. The fluorescence lifetime, tau, of 1 was determined as 18.8 ns and steadily decreased to 7.5 and 6.8 ns in the presence of 0.1 M of (S)-23 and (R)-23, respectively.
Collapse
Affiliation(s)
- Xuefeng Mei
- Department of Chemistry, Georgetown University, Washington, D.C. 20057, USA
| | | | | |
Collapse
|
23
|
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.
Collapse
Affiliation(s)
- Paolo Larini
- Dipartimento di Chimica Organica U. Schiff, Università di Firenze, Via della Lastruccia 13, I-50019 Sesto Fiorentino, Italy
| | | | | |
Collapse
|
24
|
Giese S, Mazzola RD, Amann CM, Arif AM, West FG. Unexpected Participation of an Unconjugated Olefin during Nazarov Cyclization of Bridged Bicyclic Dienones. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501737] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
25
|
Giese S, Mazzola RD, Amann CM, Arif AM, West FG. Unexpected Participation of an Unconjugated Olefin during Nazarov Cyclization of Bridged Bicyclic Dienones. Angew Chem Int Ed Engl 2005; 44:6546-9. [PMID: 16173000 DOI: 10.1002/anie.200501737] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sören Giese
- Department of Chemistry, University of Utah, 315 S. 1400 East, Room 2020, Salt Lake City, UT 84112-0850, USA
| | | | | | | | | |
Collapse
|
26
|
Li JH, Liang Y, Xie YX. An efficient Stille cross-coupling reaction catalyzed by Pd(OAc)2/DAB-Cy catalytic system. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.04.073] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
27
|
Mazzola RD, White TD, Vollmer-Snarr HR, West FG. Stereoselective Nazarov cyclizations of bridged bicyclic dienones. Org Lett 2005; 7:2799-801. [PMID: 15957950 PMCID: PMC2529303 DOI: 10.1021/ol051169q] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Bridged bicyclic dienones underwent silyl-directed Nazarov cyclization with generally very high diastereoselectivity. In most cases, a strong preference for cyclization to the product with an exo-disposed cyclopentenone was seen. However, the presence of additional unsaturation in the three-carbon bridge of a bicyclo[3.2.1]octadiene system caused complete reversal in selectivity with exclusive formation of the endo-cyclopentenone. The observed selectivities are believed to result from a combination of steric and electronic effects.
Collapse
Affiliation(s)
- Robert D Mazzola
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, USA
| | | | | | | |
Collapse
|