Download or read book Studies Toward the Enantioselective Total Synthesis of Pectenotoxin 2 written by Dmitriy A. Bondar and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Studies toward the enantioselective total synthesis of the marine natural toxin pectenotoxin 2 are described. A successful approach to a fully functionalized precursor to the C(29)-C(40) F/G sector began with the establishment of a proper stereochemical relationship between the hydroxyl and methyl substituents at C(37) and C(38) and involved an anti-aldol reaction. The F ring framework was merged by means of vinyl anion coupling. A new hydroxyl-directed hydrogenation protocol featuring ionic bonding between an alkoxide and rhodium catalyst was invented to arrest the pronounced tendency of hydroxy dihydrofurans to undergo dehydration to form more stable furans. A great level of efficiency was gained by routing the synthesis of the C(16)-C(26) subunit through a common intermediate. The carbon framework was then assembled via a Julia coupling process. The resulting double bond was oxidized by way of a Sharpless asymmetric dihydroxylation reaction to produce two new sterecenters and form the ring E tetrahydrofuranyl system. Access to the C(1)-C(15) building block was achieved by convergent coupling of a lithiated alkane to a Weinreb amide. The spirocyclic A/B motif was next constructed in a synchronous manner by two-fold p-methoxybenzyl ether deprotection. Catalytic á-hydroxylation of a conjugated double bond was called upon to complete the oxygenation pattern of this fragment. Union of the C(1)-C(15) and C(16)-C(26) fragments by means of Julia olefination led to construction of the AB(CD)E eastern hemisphere of pectenotoxin 2. Although the route to this target is far from complete, knowledge collected herein should pave the way toward completion of the total synthesis of this fascinating natural product.
Download or read book Studies Toward the Enantioselective Total Synthesis of Quadrigemine H written by Leonard Sung and published by . This book was released on 2008 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthetic efforts toward the [3+1] quadrigemine alkaloids are described in this dissertation. Chapter 1 reviews the quadrigemine alkaloids from a historical perspective and discusses methods for the construction of their highly congested vicinal and diaryl all-carbon quaternary stereocenters. The application of these methods is featured in the presentation of the enantioselective syntheses of hodgkinsine and quadrigemine C.
Download or read book Studies Toward the Enantioselective Total Synthesis of Stemonine written by Beth Ann Plattner and published by . This book was released on 1997 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies Toward the Enantioselective Total Synthesis of Manzamine A written by Matthew David Kowalski and published by . This book was released on 2008 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies Toward an Enantioselective Total Synthesis of Aleurodiscal written by Todd M. Heidelbaugh and published by . This book was released on 1996 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies Directed Toward the Enantioselective Total Synthesis of Guattegaumerine written by Cheryl Faye Lichti and published by . This book was released on 1993 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enantioselective Total Syntheses of Teubrevin G and Teubrevin H and Studies Toward the Enantioselective Total Synthesis of Vinigrol written by Ivan V. Efremov and published by . This book was released on 2001 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies Towards the Enantioselective Total Synthesis of Manzamine A written by Theodore Mark Kamenecka and published by . This book was released on 1996 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Towards the Total Synthesis of Pectenotoxin 4 written by Melodie Richardson and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies Toward the Enantioselective Synthesis of an Epidithiapiperazinedione Ring and Pummerer Reaction Chemistry written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Enantioselective Dearomatization and Studies Towards the Total Synthesis of morphine written by Robert David Matthew Pace and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book First Enantioselective Oxidative Rearrangemetn of Indoles to Spirooxindoles Studies Toward the Total Synthesis of IB 00208 and Total Synthesis of Cribrostatin 6 written by Daniel Isaiah Knueppel and published by . This book was released on 2010 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies Directed Towards the Total Synthesis of Spongistatin 1 altohyrtin A and Pectenotoxin II written by Glenn C. Micalizio and published by . This book was released on 2001 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of the Type 2 Intramolecular Diels Alder Reaction to Natural Product Synthesis I an Enantioselective Total Synthesis of adrenosterone II Studies Toward the Synthesis of 9 deoxyphorbol written by Carolyn Diane Dzierba and published by . This book was released on 1997 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enantioselective Total Synthesis of Guanacastepenes A and E written by William D. Shipe and published by . This book was released on 2004 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: The evolution of a convergent strategy that led to efficient, enantioselective syntheses of guanacastepene E and guanacastepene A (formal) is described. The first chapter of this thesis provides background information on (1) the isolation and biology of the guanacastepene family of secondary metabolites, (2) the substantial synthetic work carried out by other research groups toward their synthesis, and (3) the basis of our ultimate approach to the natural product. The synthesis of a fully functionalized C ring and two major model studies that provided critical information about the system are described in the second chapter. The final chapter describes (1) the enantiospecific synthesis of an A ring fragment from R-(-)-carvone, including a novel ring-contracting reaction, (2) the classical resolution of the C ring, and (3) the union of the two enantiopure fragments and further elaboration, culminating in the enantioselective total synthesis of both the natural (+)- and unnatural (-)-guanacastepene E and a formal total synthesis of (+)-guanacastepene A. The foundation of our convergent approach is the following sequence of three reactions: (1) the union of two functionalized building blocks through a [pi]-allyl Stille cross-coupling reaction, (2) the stereoselective construction of the C-11 quaternary carbon center with a [2+2] photocycloaddition, and (3) the stereoselective, reductive fragmentation of a cyclobutyl bond to form the seven-membered central B ring of the guanacastepenes.
Download or read book Part I the Enantioselective Total Synthesis of Antiulcerogenic Compound Cassioside written by Yugang Liu and published by . This book was released on 1997 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies Toward the Total Synthesis of Tetrapetalone A written by Eric G. Stoutenburg and published by . This book was released on 2018 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The work presented in this dissertation is a detailed account of the progress made toward the enantioselective total synthesis of tetrapetalone A. Chapter 1 provides information on the isolation and biological activity as well as past work done by other labs such as Porco, Hong, Sarpong, Pettus and Wood. Also included is a detailed account of our total synthesis of tetrapetalone A-Me aglycon that was published in 2014. Chapter 2 highlights our initial strategy towards enantioselective synthesis of the AB ring system through a Heck cyclization. Also described in chapter 2 is our strategy for enantioselective formation of an oxazolidinone that can be elaborated to the desired tetramic acid D ring. Chapter 3 describes the use of Meldrum's acid as an alternative method for the AB ring formation through the use of Friedel-Craft chemistry. Chapter 4 describes our strategy for a diastereoselective installation of the [beta]-D-rhodinose sugar and chemoselective reduction"--Page x.
