1
|
Bismuth(III)-catalyzed cascade condensation of alkynyl alcohols with terminal alkynes: a facile construction of propargyl cyclic ethers. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.154274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
2
|
Vellemäe E, Lebedev O, Sillard R, Mäeorg U. A selective method for cleavage of N-Troc-protected hydrazines and amines under mild conditions using mischmetal and TMSCl. JOURNAL OF CHEMICAL RESEARCH 2019. [DOI: 10.3184/030823406779173280] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Troc (2,2,2-trichloroethoxycarbonyl) protecting group was efficiently removed under neutral conditions from corresponding protected hydrazines and amines using mischmetal in good to excellent yields. Two new substituted hydrazines were synthesised.
Collapse
Affiliation(s)
- Eerold Vellemäe
- Institute of Organic and Bioorganic Chemistry, University of Tartu, Jakobi 2, 51014, Tartu, Estonia
| | - Oleg Lebedev
- Institute of Organic and Bioorganic Chemistry, University of Tartu, Jakobi 2, 51014, Tartu, Estonia
| | - Rannar Sillard
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171-77 Stockholm, Sweden
| | - Uno Mäeorg
- Institute of Organic and Bioorganic Chemistry, University of Tartu, Jakobi 2, 51014, Tartu, Estonia
| |
Collapse
|
3
|
Abstract
Total syntheses of biologically and structurally fascinating sesterterpenoids published between Jan. 2012 and Jan. 2018 are summarized and discussed here.
Collapse
Affiliation(s)
- Yuye Chen
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- China
- Department of Chemistry and Shenzhen Grubbs Institute
| | - Jing Zhao
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- China
| | - Shaoping Li
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- China
| | - Jing Xu
- Department of Chemistry and Shenzhen Grubbs Institute
- Southern University of Science and Technology
- Shenzhen
- China
| |
Collapse
|
4
|
Affiliation(s)
- Seewon Joung
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Rira Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Hee-Yoon Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| |
Collapse
|
5
|
Rodríguez-López J, Ortega N, Martín VS, Martín T. β-Hydroxy-γ-lactones as nucleophiles in the Nicholas reaction for the synthesis of oxepene rings. Enantioselective formal synthesis of (−)-isolaurepinnacin and (+)-rogioloxepane A. Chem Commun (Camb) 2014; 50:3685-8. [DOI: 10.1039/c4cc00389f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The enantioselective formal synthesis of (−)-isolaurepinnacin and (+)-rogioloxepane A has been achieved.
Collapse
Affiliation(s)
- Julio Rodríguez-López
- Instituto Universitario de Bio-Orgánica “Antonio González”
- CIBICAN
- Departamento de Química Orgánica
- Universidad de La Laguna (ULL)
- 38206 La Laguna, Spain
| | - Nuria Ortega
- Instituto Universitario de Bio-Orgánica “Antonio González”
- CIBICAN
- Departamento de Química Orgánica
- Universidad de La Laguna (ULL)
- 38206 La Laguna, Spain
| | - Victor S. Martín
- Instituto Universitario de Bio-Orgánica “Antonio González”
- CIBICAN
- Departamento de Química Orgánica
- Universidad de La Laguna (ULL)
- 38206 La Laguna, Spain
| | - Tomás Martín
- Instituto Universitario de Bio-Orgánica “Antonio González”
- CIBICAN
- Departamento de Química Orgánica
- Universidad de La Laguna (ULL)
- 38206 La Laguna, Spain
| |
Collapse
|
6
|
Rodríguez-López J, Pinacho Crisóstomo F, Ortega N, López-Rodríguez M, Martín VS, Martín T. Epoxide-Opening Cascades Triggered by a Nicholas Reaction: Total Synthesis of Teurilene. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201209159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
7
|
Rodríguez-López J, Pinacho Crisóstomo F, Ortega N, López-Rodríguez M, Martín VS, Martín T. Epoxide-opening cascades triggered by a Nicholas reaction: total synthesis of teurilene. Angew Chem Int Ed Engl 2013; 52:3659-62. [PMID: 23436322 DOI: 10.1002/anie.201209159] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 12/29/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Julio Rodríguez-López
- Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, Francisco Sánchez, 2, 38206 La Laguna, Tenerife, Spain
| | | | | | | | | | | |
Collapse
|
8
|
Hodgson DM, Talbot EPA, Clark BP. Synthesis of the anti-trypanosomal agent (±)-hydroxyanthecotulide by Cr(ii)-catalysed allylation and Meyer-Schuster rearrangement. Chem Commun (Camb) 2012; 48:6349. [PMID: 22614128 DOI: 10.1039/c2cc32283h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
The first synthesis of the bioactive sesquiterpene lactone hydroxyanthecotulide is achieved in 7 steps, involving a stereocontrolled Cr(ii)-catalysed reaction of 3-(bromomethyl)furan-2(5H)-one with enynal 9 and a mild Au(i)-catalysed Meyer-Schuster rearrangement.
Collapse
Affiliation(s)
- David M Hodgson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
| | | | | |
Collapse
|
9
|
Vellemäe E, Stepanov V, Mäeorg U. Mild Approach to the Deprotection of Troc from Protected Amines Using Mischmetal and TMSCl. SYNTHETIC COMMUN 2010. [DOI: 10.1080/00397910903419910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
10
|
Ortega N, Martín VS, Martín T. An Approach to Lauroxanes by Iterative Use of Co2(CO)6-Acetylenic Complexes. A Formal Synthesis of (+)-Laurencin. J Org Chem 2010; 75:6660-72. [DOI: 10.1021/jo101566x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nuria Ortega
- Departamento de Química Orgánica, Instituto Universitario de Bioorgánica “Antonio González”, Universidad de La Laguna, Astrofísico Francisco Sánchez 2, 38206 La Laguna, Tenerife, Islas Canarias, Spain
| | - Victor S. Martín
- Departamento de Química Orgánica, Instituto Universitario de Bioorgánica “Antonio González”, Universidad de La Laguna, Astrofísico Francisco Sánchez 2, 38206 La Laguna, Tenerife, Islas Canarias, Spain
| | - Tomás Martín
- Departamento de Química Orgánica, Instituto Universitario de Bioorgánica “Antonio González”, Universidad de La Laguna, Astrofísico Francisco Sánchez 2, 38206 La Laguna, Tenerife, Islas Canarias, Spain
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Astrofísico Francisco Sánchez 3, 38206 La Laguna, Tenerife, Islas Canarias, Spain
| |
Collapse
|
11
|
Ortega N, Martín T, Martín VS. Synthesis of α,α′-Disubstituted Linear Ethers by an Intermolecular Nicholas Reaction - Application to the Synthesis of (+)-cis/(-)-trans-Lauthisan and (+)-cis/(+)-trans-Obtusan. European J Org Chem 2009. [DOI: 10.1002/ejoc.200801063] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
12
|
Jervis PJ, Cox LR. Total synthesis and proof of relative stereochemistry of (-)-aureonitol. J Org Chem 2008; 73:7616-24. [PMID: 18774862 DOI: 10.1021/jo801338t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two trisubstituted epimeric tetrahydrofurans, 1 and 2, have been synthesized in order to confirm the relative stereochemistry in the natural product aureonitol. The key step in the synthesis of 1 and 2 involved a stereoselective intramolecular allylation of an allylsilane with an aldehyde, which introduced the stereotriad in the five-membered ring. The major tetrahydrofuran diastereoisomer 18 from this cyclization reaction was subsequently elaborated to tetrahydrofuran 1. Its 3-epimer (2) was then prepared from 1 via an oxidation-reduction sequence. Compound 1 exhibits identical (1)H NMR data to those reported for aureonitol, which was isolated from Helichrysum aureonitons by Bohlmann in 1979, whereas the (1)H NMR data for 2 are markedly different. The (1)H NMR data (in CDCl3, CD3OD, and C6D6) and (13)C NMR data (in CDCl3) for 1 are also identical with those reported for a natural product isolated from various Chaetomium sp. by Abraham, Seto, and Teuscher. These findings support Abraham's conclusion that the structure of aureonitol should be revised from 2 to 1. The enantioselective synthesis of 1 has also confirmed that (-)-aureonitol isolated by Abraham contains the (2S,3R,4S) absolute configuration of stereocenters on the tetrahydrofuran ring.
Collapse
Affiliation(s)
- Peter J Jervis
- School of Chemistry, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | | |
Collapse
|
13
|
Synthesis of six-membered oxygenated heterocycles through carbon–oxygen bond-forming reactions. Tetrahedron 2008. [DOI: 10.1016/j.tet.2007.11.092] [Citation(s) in RCA: 212] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
14
|
Guillarme S, Plé K, Banchet A, Liard A, Haudrechy A. Alkynylation of chiral aldehydes: alkoxy-, amino-, and thio-substituted aldehydes. Chem Rev 2007; 106:2355-403. [PMID: 16771453 DOI: 10.1021/cr0509915] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stéphane Guillarme
- Laboratoire de Glycosynthèse, UMR 6519, UFR Sciences Exactes et Naturelles, Bât. 18, BP 1039, 51687 Reims Cedex 2, France
| | | | | | | | | |
Collapse
|
15
|
Carrillo R, León LG, Martín T, Martín VS, Padrón JM. Synthesis and antiproliferative activity of (2R,3R)-disubstituted tetrahydropyrans. Part 2: Effect of side chain homologation. Bioorg Med Chem Lett 2007; 17:780-3. [PMID: 17110107 DOI: 10.1016/j.bmcl.2006.10.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 10/23/2006] [Accepted: 10/24/2006] [Indexed: 11/30/2022]
Abstract
In this study, we synthesized a series of enantiomerically pure (2R,3R)- and (2R,3S)-disubstituted tetrahydropyrans bearing a CH2O spacer group on the side chain at position 2 of the heterocyclic ring. The in vitro antiproliferative activities of the compounds were examined in the human solid tumor cell lines A2780 (ovarian cancer), SW1573 (non-small cell lung cancer), and WiDr (colon cancer). Overall, the results point out the relevance for antiproliferative activity of the distance between the heterocycle and the unsaturated group.
Collapse
Affiliation(s)
- Romen Carrillo
- Instituto Universitario de Bio-Orgánica Antonio González (IUBO-AG), Universidad de La Laguna, C/Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain
| | | | | | | | | |
Collapse
|
16
|
Konno T, Nagai G, Ishihara T. A novel synthetic approach to fluorine-containing acetylenic compounds based on Nicholas reaction. J Fluor Chem 2006. [DOI: 10.1016/j.jfluchem.2005.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
17
|
Díaz DD, Ramírez MA, Martín VS. [1,3]-Transfer of Chirality during the Nicholas Reaction in γ-Benzyloxy Propargylic Alcohols. Chemistry 2006; 12:2593-606. [PMID: 16400697 DOI: 10.1002/chem.200501127] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A highly regio- and stereoselective intramolecular [1,5]-hydrogen-transfer process is described. Treatment of gamma-benzyl-protected Co2(CO)6-alpha,gamma-acetylenic diols with BF3 x OEt2 provides bis-homopropargylic alcohols. The reaction occurs within seconds, tolerates a wide range of functionalities, and provides good yields. When the ether group is located at a stereochemically defined carbon atom, the rearrangement occurs with high stereoselectivity, transferring the chirality of the carbinol center to the newly created stereocenter. The cleavage of the benzyloxy group is totally regioselective when additional benzyl ethers are present. The scope and limitations of this novel process in densely substituted substrates are evaluated, and possible competitive reactions and/or stereochemical influences are also described. A mechanism based on a highly ordered chair-like transition state substantiated by a theoretical study is also included.
Collapse
Affiliation(s)
- David D Díaz
- Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, C/Astrofísico Francisco Sánchez, 2, 38206 La Laguna, Tenerife, Spain
| | | | | |
Collapse
|
18
|
Pinacho Crisóstomo FR, Carrillo R, León LG, Martín T, Padrón JM, Martín VS. Molecular Simplification in Bioactive Molecules: Formal Synthesis of (+)-Muconin. J Org Chem 2006; 71:2339-45. [PMID: 16526782 DOI: 10.1021/jo0524674] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The concept of molecular simplification as a drug design strategy to shorten synthetic routes, while keeping or enhancing the biological activity of the lead drug, has been applied to (+)-muconin, an acetogenin with remarkable cytotoxicity. A novel approach that enables the stereoselective synthesis of such a natural compound or its enantiomer from a common precursor is described. An additional advantage of the method is complete stereochemical control and the decrease in the number of chemical steps required, thus providing an enhancement of the overall yield. Antiproliferative studies against the human solid tumor cell lines showed that the aliphatic chain-THF/THP fragment of (+)-muconin has modest cytotoxic activity. The strategy opens the way to preparing novel bioactive acetogenin analogues by shorter synthetic routes.
Collapse
Affiliation(s)
- Fernando R Pinacho Crisóstomo
- Instituto Universitario de Bio-Organica Antonio Gonzalez, Universidad de La Laguna, Astrofísico Astrofísico Francisco Sanchez 2, 38206 La Laguna, Tenerife, Islas Canarias, Spain
| | | | | | | | | | | |
Collapse
|
19
|
|
20
|
Miranda PO, Ramírez MA, Padrón JI, Martín VS. In situ generation of 2,3-allenolates in the coupling of secondary homopropargylic alcohols and aldehydes. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2005.11.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
21
|
Fan M, Yan Z, Liu W, Liang Y. DABCO-Catalyzed Reaction of α-Halo Carbonyl Compounds with Dimethyl Acetylenedicarboxylate: A Novel Method for the Preparation of Polysubstituted Furans and Highly Functionalized 2H-Pyrans. J Org Chem 2005; 70:8204-7. [PMID: 16277350 DOI: 10.1021/jo050903g] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[Chemical reaction: see text] Polysubstituted furans and highly functionalized 2H-pyrans were prepared in good yields by DABCO-catalyzed reactions of alpha-halo carbonyl compounds with dimethyl acetylenedicarboxylate (DMAD) at room temperature.
Collapse
Affiliation(s)
- Mingjin Fan
- State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, PR China
| | | | | | | |
Collapse
|
22
|
Donadel OJ, Martín T, Martín VS, Villar J, Padrón JM. The tert-butyl dimethyl silyl group as an enhancer of drug cytotoxicity against human tumor cells. Bioorg Med Chem Lett 2005; 15:3536-9. [PMID: 15990300 DOI: 10.1016/j.bmcl.2005.05.126] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 05/16/2005] [Accepted: 05/18/2005] [Indexed: 11/26/2022]
Abstract
In this study, we synthesized a series of enantiomerically pure (2R,3S)-disubstituted tetrahydropyranes with diverse functional groups using known methodologies. In addition to the tert-butyl dimethyl silyl group, other common protecting groups for hydroxyl groups such as allyl, acetate, and benzoate were used to obtain appropriate derivatives. Pure compounds were evaluated in vitro against HL60 human leukemia cells and MCF7 human breast cancer cells. From the growth inhibition data a structure-activity relationship was obtained. Overall the results point to the relevant role of the tert-butyl dimethyl silyl group in the modulation of cytotoxic activity.
Collapse
Affiliation(s)
- Osvaldo J Donadel
- Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, C/ Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain
| | | | | | | | | |
Collapse
|
23
|
|
24
|
Lowe JT, Panek JS. Stereocontrolled [4+2]-Annulation Accessing Dihydropyrans: Synthesis of the C1a-C10 Fragment of Kendomycin. Org Lett 2005; 7:1529-32. [PMID: 15816744 DOI: 10.1021/ol0501875] [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: 11/30/2022]
Abstract
[reaction: see text] Development of new organosilane reagents bearing C-centered chirality where the stereocenter is fully substituted, and their use in the stereocontrolled synthesis of cis- and trans-dihydropyrans containing a trisubstituted olefin is described. The reagents participate in Lewis acid promoted [4+2]-annulations providing useful levels of selectivity with both aliphatic and aromatic aldehydes. A stereoselective synthesis of the C1a-C10 fragment of kendomycin (1) is also described.
Collapse
Affiliation(s)
- Jason T Lowe
- Department of Chemistry and Center for Chemical Methodology and Library Development, Metcalf Center for Science and Engineering, 590 Commonwealth Avenue, Boston University, Boston, Massachusetts 02215, USA
| | | |
Collapse
|
25
|
Fujiwara K, Murai A. Recent Advances in the Synthesis oftrans-Fused Polycyclic Ethers by Hydroxy-Epoxide-Cyclization and Ether-Ring-Expansion Reactions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2004. [DOI: 10.1246/bcsj.77.2129] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
26
|
Miranda PO, Díaz DD, Padrón JI, Ramírez MA, Martín VS. Fe(III) Halides as Effective Catalysts in Carbon−Carbon Bond Formation: Synthesis of 1,5-Dihalo-1,4-dienes, α,β-Unsaturated Ketones, and Cyclic Ethers. J Org Chem 2004; 70:57-62. [PMID: 15624906 DOI: 10.1021/jo048410j] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron(III) halides have proven to be excellent catalysts in the coupling of acetylenes and aldehydes. When terminal acetylenes were used the main products obtained were 1,5-dihalo-1,4-dienes with (E,Z)-stereochemistry contaminated in some cases with (E)-alpha,beta-unsaturated ketones. The former carbonyl derivatives were the sole products isolated when nonterminal aromatic alkynes were used. When homopropargylic alcohols were used, a Prins-type cyclization occurred yielding 2-alkyl-4-halo-5,6-dihydro-2H-pyrans. In addition, anhydrous ferric halides are also shown to be excellent catalysts for the standard Prins cyclization with homoallylic alcohols. Isolation of an intermediate acetal, calculations, and alkyne hydration studies provide substantiation of a proposed mechanism.
Collapse
Affiliation(s)
- Pedro O Miranda
- Instituto Universitario de Bio-Orgánica Antonio González and Departamento de Física Básica, Universidad de La Laguna, C/Astrofísico Francisco Sánchez s/n, 38206 La Laguna, Tenerife, Canary Islands, Spain
| | | | | | | | | |
Collapse
|
27
|
Crisóstomo FRP, Martín T, Martín VS. Stereoselective Intramolecular Nicholas Reaction Using Epoxides as Nucleophiles. Org Lett 2004; 6:565-8. [PMID: 14961624 DOI: 10.1021/ol0363570] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The intramolecular nucleophilic attack of the epoxides on the exo-Co(2)(CO)(6)-propargylic cations provided cyclic ethers in good yields. The use of substrates with stereochemically defined oxiranes provided polysubstituted tetrahydropyrans and oxepanes with a high degree of stereocontrol. The cyclization is sensitive to the nature of the protecting group used at the primary alcohol, the use of tert-butyl carbonates being highly effective in terms of regioselectivity and yields.
Collapse
Affiliation(s)
- Fernando R P Crisóstomo
- Instituto Universitario de Bio-Orgánica "Antonio González", Universidad de La Laguna,C/Astrofísico Francisco Sánchez, 2, 38206 La Laguna, Tenerife, Spain
| | | | | |
Collapse
|
28
|
Greeves N, Lee WM, McLachlan SP, Oakes GH, Purdie M, Bickley JF. Short synthesis of a tetrasubstituted tetrahydropyran with five stereogenic centres—stereoselective double tandem rearrangements and cyclisation. Tetrahedron Lett 2003. [DOI: 10.1016/j.tetlet.2003.09.209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
29
|
Miranda PO, Díaz DD, Padrón JI, Bermejo J, Martín VS. Iron(III)-catalyzed Prins-type cyclization using homopropargylic alcohol: a method for the synthesis of 2-alkyl-4-halo-5,6-dihydro-2H-pyrans. Org Lett 2003; 5:1979-82. [PMID: 12762701 DOI: 10.1021/ol034568z] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] A new Prins-type cyclization between homopropargylic alcohol and aldehydes in the presence of FeX(3) to obtain 2-alkyl-4-halo-5,6-dihydro-2H-pyrans in good yield is described. Osmium-catalyzed cis dihydroxylation provided direct access to trans-2-alkyl-3-hydroxy-tetrahydro-pyran-4-ones. Anhydrous ferric halides are also shown to be excellent catalysts for the standard Prins cyclization using homoallylic alcohol. Isolation of an intermediate acetal provides substantiation of a proposed mechanism.
Collapse
Affiliation(s)
- Pedro O Miranda
- Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, C/Astrofísico Francisco Sánchez 2, 38206 La Laguna, Tenerife, Spain
| | | | | | | | | |
Collapse
|