1
|
Earl ADW, Li FF, Ma C, Furkert DP, Brimble MA. Stereoselective synthesis of the spirocyclic core of 13-desmethyl spirolide C using an aza-Claisen rearrangement and an exo-selective Diels-Alder cycloaddition. Org Biomol Chem 2023; 21:1222-1234. [PMID: 36633001 DOI: 10.1039/d2ob01992b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
13-Desmethyl spirolide C is a marine natural product of the cyclic imine class that demonstrates remarkable bioactivity against several biomarkers of Alzheimer's Disease, which renders its [7,6]-spirocyclic imine pharmacophore of significant synthetic interest. This work describes a facile and efficient synthesis of the [7,6]-spirocyclic core of 13-desmethyl spirolide C from inexpensive starting materials, featuring an aza-Claisen rearrangement to simultaneously set both stereocentres of the dimethyl moiety with complete atom economy, and a highly exo-selective Diels-Alder cycloaddition to construct the challenging contiguous tertiary and quaternary stereocentres of the spirocyclic core of 13-desmethyl spirolide C. A comprehensive study of the key Diels-Alder reaction was also performed to evaluate the stereoselectivity and reactivity of various functionalised dienes and protected lactam dienophiles, wherein the first successful exo-selective Diels-Alder cycloaddition to construct spirocyclic structures using a bromodiene and α-exo-methylene dienophiles is reported. This strategy not only establishes a more efficient stereoselective access to the spirocyclic core that can be used for the total synthesis of 13-desmethyl spirolide C, but also serves as a sound platform for convenient preparations of a range of spirocyclic analogues required for a comprehensive biological evaluation of this desirable pharmacophore.
Collapse
Affiliation(s)
- Andrew D W Earl
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
| | - Freda F Li
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| | - Chao Ma
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
| | - Daniel P Furkert
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| | - Margaret A Brimble
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| |
Collapse
|
2
|
Skaria M, Culpepper JD, Daly SR. Leveraging Metal and Ligand Reactive Sites for One Pot Reactions: Ligand-Centered Borenium Ions for Tandem Catalysis with Palladium. Chemistry 2022; 28:e202201791. [PMID: 35997655 PMCID: PMC9828003 DOI: 10.1002/chem.202201791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Indexed: 01/12/2023]
Abstract
Tandem catalysts that perform two different organic transformations in a single pot are highly desirable because they enable rapid and efficient assembly of simple organic building blocks into more complex molecules. Many examples of tandem catalysis rely on metal-catalyzed reactions involving one or more metal complexes. Remarkably, despite surging interest in the development of chemically reactive (i. e., non-innocent) ligands, there are few examples of metal complexes that leverage ligand-centered reactivity to perform catalytic reactions in tandem with separate catalytic reactions at the metal. Here we report how multifunctional Pd complexes with triaminoborane-derived diphosphorus ligands, called TBDPhos, appear to facilitate borenium-catalyzed cycloaddition reactions at the ligand, and Pd-catalyzed Stille and Suzuki cross-coupling reactions at the metal. Both transformations can be accessed in one pot to afford rare examples of tandem catalysis using separate metal and ligand catalysis sites in a single complex.
Collapse
Affiliation(s)
- Manisha Skaria
- Department of ChemistryThe University of IowaIowa CityIowa52242USA
| | | | - Scott R. Daly
- Department of ChemistryThe University of IowaIowa CityIowa52242USA
| |
Collapse
|
3
|
Wang Z, Yamazaki S, Mikata Y, Oba M, Takashima H, Morimoto T, Ogawa A. Intramolecular Diels-Alder Reactions of α-Bromostyrene-Functionalized Unsaturated Carboxamides. J Org Chem 2022; 87:11148-11164. [PMID: 35944162 DOI: 10.1021/acs.joc.2c01417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intramolecular cycloaddition reactions of α-bromostyrene-functionalized amides of monomethyl fumarate were investigated. The reaction of the amides with Et3N in toluene at 110 °C gave 1,4-dihydronaphthalenes. The 1,4-dihydronaphthalenes may be produced via the intramolecular Diels-Alder reaction, proton transfer, and dehydrobromination by a base, along with C═C bond isomerization by proton transfer. The reaction of amide derivatives with halogen on a benzene ring and alkali metal carbonates in toluene at 110 °C gave naphthalene derivatives directly. Dehydrogenation of various 1,4-dihydronaphthalenes with cesium or rubidium carbonate in toluene at 110 °C gave naphthalene derivatives. The retardation by TEMPO, acceleration by air for some substrates, and density functional theory calculations suggest a radical mechanism caused by intervention of molecular oxygen.
Collapse
Affiliation(s)
- Zhichao Wang
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Nakaku, Sakai, Osaka 599-8531, Japan
| | - Shoko Yamazaki
- Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan
| | - Yuji Mikata
- Laboratory for Molecular and Functional Design, Department of Engineering, Nara Women's University Nara 630-8506, Japan
| | - Miho Oba
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Hiroshi Takashima
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Tsumoru Morimoto
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Takayama, Ikoma, Nara 630-0192, Japan
| | - Akiya Ogawa
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Nakaku, Sakai, Osaka 599-8531, Japan
| |
Collapse
|
4
|
Bakthadoss M, Mushaf M, Agarwal V, Reddy TT, Sharada DS. Azomethine ylide cycloaddition of 1,3-dienyl esters: highly regio- and diastereoselective synthesis of functionalized pyrrolidinochromenes. Org Biomol Chem 2022; 20:778-782. [PMID: 35024708 DOI: 10.1039/d1ob02042k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient protocol for the synthesis of tricyclic pyrrolidinochromenes has been developed via an intramolecular 1,3-dipolar cycloaddition of azomethine ylides generated in situ from 1,3-dienyl ester tethered O-hydroxyarylaldehyde and glycine esters. The reaction is highly regio- and diastereoselective in nature and provided the potentially bioactive pyrrolidine fused tricyclic cycloadducts in excellent yields with wide substrate scope. Interestingly this reaction constructs two rings and four contiguous stereogenic centers in which one of them is an all carbon quaternary center in a unique fashion.
Collapse
Affiliation(s)
- Manickam Bakthadoss
- Department of Chemistry, Pondicherry University, Pondicherry - 605 014, India.
| | - Mohammad Mushaf
- Department of Chemistry, Pondicherry University, Pondicherry - 605 014, India.
| | - Vishal Agarwal
- Department of Chemistry, Pondicherry University, Pondicherry - 605 014, India.
| | | | - Duddu S Sharada
- Department of Chemistry, Indian Institute of Technology, Hyderabad, Telangana-502285, India
| |
Collapse
|
5
|
Li L, Turnbull WL, McDonald R, West FG. Lithium Hydroxide Assisted
Endo
‐Selective [4+4]‐Photocycloaddition of Pyran‐2‐ones. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lei Li
- Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
| | - William L. Turnbull
- Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
| | - Robert McDonald
- X-Ray Crystallography Laboratory Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
| | - F. G. West
- Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
| |
Collapse
|
6
|
Singh H, Rajeshwari M, Khurana J. Synthesis, photophysical studies, and application of novel 2,7-bis((1-butyl-1H-1,2,3-triazol-4-yl)methoxy)naphthalene as a highly selective, reversible fluorescence chemosensor for detection Fe3+ ions. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|