Download or read book Studies on Cyclic Ether Formation written by Harriet Ann Woolven and published by . This book was released on 1992 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies in Cyclic Ether Synthesis written by Romain Frédéric Cadou and published by . This book was released on 2010 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies in Cyclic Ether Synthesis written by Romain F. Cadou and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tetrahydrofuran (THF) and tetrahydropyran (THP) rings are commonly found in a wide range of natural products and biologically active compounds. In total synthesis, the formation of THF/THP motifs is often the key step but existing methods often involve numerous steps and low overall efficiencies. Part one of this thesis details the development of a practical method for the synthesis of THF rings by the controlled mono-addition/cyclisation of organolithium species to C2-symmetric diepoxides (Scheme A-1). This method can also be applied to the synthesis of bis-THF rings from triepoxides and has potential applications in more complex cascade reactions. A similar cyclisation process providing THF rings from epoxyaldehydes is also described. Part two of this thesis details our efforts towards the synthesis of the marine macrolide neopeltolide. Wright and co-workers reported the isolation of neopeltolide 211 from a deep-water sponge of the family neopeltidae off the north coast of Jamaica. The structure, which was assigned by NMR and HRMS studies and reassigned by total synthesis, contains a 14-membered macrolactone, a 2,6-cis THP ring and an unsaturated oxazole side-chain. Chapter four describes the synthesis of the C2-C8 and C9-C16 fragments (Scheme A-2). Chapter five details our initial attempts in the coupling of subunits 268 and 320, as well as a revised synthetic strategy that allowed us to successfully couple C2-C9 alkyne 347 with C10-C16 aldehyde 348 and the preparation of an advanced intermediate 364 (Scheme A-3).
Download or read book Cyclic Ethers Advances in Research and Application 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclic Ethers: Advances in Research and Application: 2011 Edition is a ScholarlyBrief™ that delivers timely, authoritative, comprehensive, and specialized information about Cyclic Ethers in a concise format. The editors have built Cyclic Ethers: Advances in Research and Application: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Cyclic Ethers in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Cyclic Ethers: Advances in Research and Application: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Methodologies in Ether Synthesis written by Zahra Taherinia and published by Royal Society of Chemistry. This book was released on 2024-08-16 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ethers and crown ethers are important structural parts of many man-made or natural organic materials with medicinal, agrochemical or technological attributes. In recent years, extensive studies have been conducted for developing novel ether synthesis methods. This book summarizes recent advances in synthesizing dialkyl, alkyl aryl, diaryl, cyclic, and crown ethers. It also discusses their substantial applications in various fields such as organic synthesis, ionic liquids, protecting groups, photoswitchable catalysis, phase transfer catalysts, solvents, biological functionality, anticancer properties and antimicrobial effects, drug delivery, and biofuels. Providing an invaluable reference for undergraduates, postgraduates and researchers interested in organic chemistry, it also contributes to the literature for chemical researchers working in industry.
Download or read book A Study of the Formation and Structure of Cyclic Ethers from Ortho Allyl Phenols written by Hubert W. Moor and published by Forgotten Books. This book was released on 2017-10-28 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from A Study of the Formation and Structure of Cyclic Ethers From Ortho Allyl Phenols: Thesis The chromenes represent a comparatively unstudied field in organic chemistry since no other work than that related above has been done on them. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Download or read book A Study of the Formation and Structure of Cyclic Ethers from Ortho Allyl Phenols written by Hubert W. Moor and published by . This book was released on 1917 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cyclic Ethers Advances in Research and Application 2012 Edition written by and published by ScholarlyEditions. This book was released on 2012-12-26 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclic Ethers—Advances in Research and Application: 2012 Edition is a ScholarlyBrief™ that delivers timely, authoritative, comprehensive, and specialized information about Cyclic Ethers in a concise format. The editors have built Cyclic Ethers—Advances in Research and Application: 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Cyclic Ethers in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Cyclic Ethers—Advances in Research and Application: 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Part I Studies on the Cyclization of Cyclic Vinyl Ether Epoxides written by Jayaram Ragupathy Tagat and published by . This book was released on 1984 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Sterochemistry of Cyclic Ether Formation by Lead Tetraacetate written by Mary Jane Lounsbury Rafuse and published by . This book was released on 1966 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Formation of Cyclic Ethers from Diols and Pentaethoxyphosphorane written by John Joseph Gigantino and published by . This book was released on 1986 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stereospecific Cyclic Ether Formation with Phenylthio Migration written by Francis Hugh Sansbury and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cyclic Ether Synthesis Via Lewis Acid Promoted Carbon carbon Bond Forming Cyclization Reactions of Unsaturated and Saturated Symmetric Acetals written by Elizabeth Gonda and published by . This book was released on 1988 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Novel Aromatic C Ring Taxol Analogs Toward a Synthesis of a Brevetoxin B Analog New Methods for the Construction of Cyclic Ethers written by Christopher Fairman Claiborne and published by . This book was released on 1996 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model studies were carried out on key steps directed toward a synthesis of taxol. A model aromatic taxol C ring was coupled to taxol A ring via the Shapiro reaction. Selective functionalization of the A ring was carried out by epoxidation of the allylic alcohol derived from Shapiro coupling. Compatible protecting groups were found to rigidity the model AC framework in preparation for cyclization of the B ring. The McMurry reaction was established as an effective method for the formation of the eight membered B ring. Selective functionalization of the C-13 position of the A ring by PCC oxidation was accomplished. Controlled reduction of the C-13 ketone was carried out and subsequent coupling to the taxol side chain was achieve by the Oijima-Holton method. A biologically active analog of taxol was synthesized. Toward a synthesis of a brevetoxin B analog, a model ABC ring fragment was synthesized by established 6 -endo hydroxy-epoxide cyclizations. A model EF ring system was also synthesized by similar methods. Variations on the ABC fragment were independently coupled to the FG fragment and in a novel titanium mediated metathesis, the D ring was formed. Functionalization of the resulting D ring enol ether set the stage for the formation of the E ring via a hydroxy-ketone condensation. A hexacyclic (B - G) and heptacyclic (A - G) fused polyether ring systems were synthesized during our efforts to prepare a brevetoxin B analog.
Download or read book Gold I catalyzed Rearrangements of Allyl Aryl Ethers written by Heidi E. Dimmitt and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gold catalyzed reactions are an active area of interest for synthetic chemists due to gold's ability to promote formation of carbon-carbon bonds. A mechanistic study of the aromatic Claisen rearrangement of allyl aryl ethers in the presence of a gold catalyst has shed some light on the role of the gold catalyst in this reaction. Studies probing the electronics requirements of the reaction as well as investigation of stereochemical conservation both support a dissociative ionic mechanism. Our data supports that the catalyst interacts primarily with the alkene branch as opposed to the phenoxide oxygen because the E and Z allyl aryl ether diastereomers form different ratios of the [3,3] and [1,3] rearrangement products. NMR studies have caused us to question our presumed active catalyst, Ph3PAuOTf, and we now suspect gold nanoparticles or a thin gold film are catalyzing the rearrangement. Through investigations of the synthetic scope of our gold catalyst, some unexpected reaction products were produced. A cyclic ether formed when the allyl branch contained an acetonide protecting group. This cyclization was even more effective when the acetonide was first converted to the corresponding diol. This cyclic ether formation was put to practical use in the total synthesis of the natural product (±)-centrolobine.
Download or read book Computational Theoretical Organic Chemistry written by Imre G. Csizmadia and published by Springer. This book was released on 1981-04-30 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Study Institute, Menton, France, June 29-July 13, 1980
Download or read book Rhodium Porphyrin Alkylations with Ammonium and Quinolinium Salts and Cyclic Ether Formation Via a Palladium Catalyzed Dehydrogenative Annulation written by Samuel John Thompson and published by . This book was released on 2016 with total page 1304 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation and study of metal–carbon [greek small letter sigma]-bonds can help unveil unique reactivities of organometallic complexes and provide support for further catalytic transformations. Rhodium porphyrins have shown exceptional reactivity through radical- type transformations, attracting significant attention towards understanding these metalloradical-mediated mechanisms. The stability and selectivity of rhodium porphyrins are promising for catalytic transformations, however, strong rhodium–carbon bonds frequently limit catalyst turnover. To gain a better understanding of Rh–C bonds in the porphyrin system, the synthesis of alkyl rhodium porphyrins through a C–N bond dealkylation of ammonium and quinolinium salts was conducted. The organometallic complexes were formed under air and with water, serving as a convenient method to prepare Rh–C bonds. Mechanistic studies support rhodium(I), rhodium(II), and rhodium(III) porphyrin intermediates operating in the alkylation, with a SN2-like reaction in the Rh–C bond forming step. A directed sp3 C–H bond functionalization strategy was also investigated to accomplish cyclic ether formation via an intramolecular alkoxylation reaction. An oxime vii directing group provided chemoselective activation at [greek small letter beta]-methyl positions, forming annulated products from the addition of tethered alcohol nucleophiles. Four- to seven- membered rings could be accessed through this dehydrogenative annulation pathway. Tethered primary, secondary, and tertiary free hydroxyl groups can all react to give the corresponding cyclized products. Protected silyl and benzyl alcohols were also compatible nucleophiles for the coupling. Preliminary mechanistic analysis supports an sp3 C–H activation/intramolecular SN2 pathway.
