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Enantioselective Total Synthesis Of Shahamin K And Enantioselective Total Synthesis Of Quadrigemine C And Psycholeine
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Book Synopsis Enantioselective Total Synthesis of Shahamin K and Enantioselective Total Synthesis of Quadrigemine C, and Psycholeine by : Alec Donald Lebsack
Download or read book Enantioselective Total Synthesis of Shahamin K and Enantioselective Total Synthesis of Quadrigemine C, and Psycholeine written by Alec Donald Lebsack and published by . This book was released on 2002 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies Toward the Enantioselective Total Synthesis of Quadrigemine H by : Leonard Sung
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.
Book Synopsis Enantioselective Total Synthesis of (+)- KB343 by : Cheng Bi
Download or read book Enantioselective Total Synthesis of (+)- KB343 written by Cheng Bi and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Chemical Synthesis by : Elias J. Corey
Download or read book Enantioselective Chemical Synthesis written by Elias J. Corey and published by Elsevier. This book was released on 2013-10-23 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by world-renowned and best-selling experts, Nobel Laureate E. J. Corey and Laszlo Kurti, Enantioselective Chemical Synthesis offers an authoritative and comprehensive overview of the field's progress; the processes and tools for key formations; future development for complex, stereocontrolled (enantiomeric or diastereoisomeric) molecules; and valuable examples of multi-step syntheses. Utilizing a color-coded scheme to illustrate chemical transformations, Enantioselective Chemical Synthesis provides clear explanation and guidance through vital asymmetrical syntheses and insight into the next steps for the field. Researchers, professionals, and academics will benefit from this valuable, thorough, and unique resource. - In Part I, the authors present clearly, comprehensively and concisely the most useful enantioselective processes available to synthetic chemists. - Part II provides an extensive discussion of the most logical ways to apply these new enantioselective methods to the planning of syntheses of stereochemically complex molecules. This hitherto neglected area is essential for the advancement of enantioselective synthesis to a more rational and powerful level. - Part III describes in detail many reaction sequences which have been used successfully for the construction of a wide variety of complex target molecules - Clearly explains stereochemical synthesis in theory and practice - Provides a handy tool box for scientists wishing to understand and apply chiral chemical synthesis - Describes almost 50 real life examples of asymmetric synthesis in practice and examines how the chiral centers were introduced at key synthetic stages
Book Synopsis Enantioselective Total Synthesis of (+)-isolaurepinnacin and Enantioselective Total Synthesis of ( - )-ptilomycalin A by : Paul Allan Renhowe
Download or read book Enantioselective Total Synthesis of (+)-isolaurepinnacin and Enantioselective Total Synthesis of ( - )-ptilomycalin A written by Paul Allan Renhowe and published by . This book was released on 1995 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Synthesis of (+)-arborescidine C and Related Tetracyclic Indole Alkaloids Using Organocatalysis by : 賽思
Download or read book Enantioselective Total Synthesis of (+)-arborescidine C and Related Tetracyclic Indole Alkaloids Using Organocatalysis written by 賽思 and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies Towards the Enantioselective Total Synthesis of Manzamine A by : Theodore Mark Kamenecka
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:
Book Synopsis Total Synthesis of Cyclotryptamine and Diketopiperazine Alkaloids and Biosynthetic Pathway Investigation of Unsymmetrical Diketopiperazine Dimers by : Petra Lindovská
Download or read book Total Synthesis of Cyclotryptamine and Diketopiperazine Alkaloids and Biosynthetic Pathway Investigation of Unsymmetrical Diketopiperazine Dimers written by Petra Lindovská and published by . This book was released on 2018 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: I. Total Synthesis of (-)-Hodgkinsine, (-)-Calycosidine, (-)-Hodgkinsine B, (-)-Quadrigemine C and (-)-Psycholeine The enantioselective total synthesis of (-)-hodgkinsine, (-)-calycosidine, (-)-hodgkinsine B, (-)- quadrigemine C, and (-)-psycholeine through a diazene-directed assembly of cyclotryptamine fragments is described. Our synthetic strategy enables multiple and directed assembly of intact cyclotryptamine subunits for convergent synthesis of highly complex bis- and tris-diazene intermediates. Photoextrusion of dinitrogen from these intermediates enables completely stereoselective formation of all C3a-C3a' and C3a-C7' carbon-carbon bonds and all the associated quaternary stereogenic centers. The synthesis of these complex diazenes was made possible through a new methodology for synthesis of aryl-alkyl diazenes using electronically attenuated hydrazine-nucleophiles in a silver-promoted addition to C3a-bromocyclotryptamines. The application of Rh- and Ir-catalyzed C-H amination reactions in complex settings were used to gain rapid access to C3a- and C7-functionalized cyclotryptamine monomers, respectively, used for diazene synthesis. II. Total Synthesis of (-)-Naseseazine C and Identification of its Biosynthetic Pathway The biogenesis of unsymmetrical dimeric diketopiperazines is investigated, in collaboration with the Sherman group at the University of Michigan. Sequencing and mining the genome of Streptomyces sp. CB MQ-030, known to produce unsymmetrical diketopiperazine dimers, allowed the identification of NasB, a cytochrome P450 responsible for catalyzing late-stage oxidative dimerization of brevianamide F into (-)-naseseazine C. The relative and absolute stereochemical assignment was confirmed via its total synthesis using highly convergent late-stage fragment union of complex diketopiperazines.
Book Synopsis Enantioselective Total Synthesis of (-)-16-Hydroxytriptolide by : Bob Lui
Download or read book Enantioselective Total Synthesis of (-)-16-Hydroxytriptolide written by Bob Lui and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Enantioselective Total Synthesis of (-)-16-hydroxytriptolide" by Bob, Lui, 呂思奇, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled ENANTIOSELECTIVE TOTAL SYNTHESIS OF (-)-16-HYDROXYTRIPTOLIDE Submitted by Lui Bob for the degree of Doctor of Philosophy at The University of Hong Kong in August 2005 (-)-16-Hydroxytriptolide, a natural product isolated from the Chinese medicinal plant Tripterygium wilfordii Hook F (Lei Gong Teng), shows potent immunosuppressive, antileukemic, and antineuropathic activities. The goal of this project is to develop an enantioselective total synthesis of (-)-16-hydroxytriptolide. The results are summarized as follows. (1) A convergent and efficient synthetic scheme towards ()-16-hydroxytriptolide ()-3.19a has been developed using 2-methylanisole as the starting material. This route involves 21 steps in a 1.8% total yield. The key steps include (i) radical cyclization of ()-3.1 mediated by Mn(OAc) -2HO, (ii) 3 2 α,β-unsaturated γ-lactone construction of ()-3.3, (iii) side-chain installation by Sonogashira coupling from ()-Q5, and (iv) triepoxide construction from ()-3.12. (2) Following a similar synthetic scheme as that of ()-16-hydroxytriptolide, the enantioselective synthesis of (-)-16-hydroxytriptolide has been accomplished. This route involves 21 steps in a 2.4% total yield. The chirality of the trans-ring juncture of the tricyclic core was established by diastereoselective radical cyclization using (+)-8-phenylmenthol as the chiral auxiliary (73% yield, 34:1 dr). The chiral induction of side chain at C-15 was achieved by asymmetric hydrogenation (90% yield, 5.3:1 dr). (3) α-Halogenation reactions of 1,3-dicarbonyl compounds have been investigated to improve the synthetic efficiency of ()-16-hydroxytriptolide. The effect of Lewis acids was examined. In the absence of Lewis acid, the α-bromination of 1,3-dicarbonyl compounds 4.1f afforded both di-brominated 4.4f and mono-brominated products 4.3f in poor yield and selectivity (45%, 4.3f:4.4f = 1.5:1). However, when the α-bromination reaction was carried out in the presence of 0.3 equiv of Mg(ClO ) at room temperature, both the yield and the selectivity of 4 2 α-monobromination improved significantly (85%, 4.3f:4.4f = 14.8:1). (4) In connection to the asymmetric radical cyclization of 5.1 using (+)-8-phenylmenthol as the chiral auxiliary, a one-pot synthesis of its precursor, (S)-(-)-pulegone, has been developed. The reaction of LiClO (0.1 equiv), IBX (3 equiv), and (S)-(-)-citronellol in EtOAc under reflux for 17 h followed by basic treatment, led to a high chemical yield (90%) of (S)-(-)-pulegone. This provides an efficient and economical means to afford (+)-8-phenylmenthol for our (-)-16-hydroxytriptolide synthesis. OMe OMe O OMe H H Cl CO Me CO Me 2 (-)-3.3 (-)-Q5 O (-)-3.1 OH OMe O HO HO C H O O H O O (-)-3.19a (-)-3.12 O O O O O O Ph OEt Ph OEt Ph OEt Br Br Br 4.3f 4.4f 4.1f DOI: 10.5353/th_b3636945 Subjects: Terpenes Organic compounds - Synthesis Medicinal plants - Analysis
Book Synopsis Studies Toward the Enantioselective Total Synthesis of Manzamine A by : Matthew David Kowalski
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:
Book Synopsis Enantioselective Total Synthesis of Cyathin A3 by :
Download or read book Enantioselective Total Synthesis of Cyathin A3 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies Toward the Enantioselective Total Synthesis of Stemonine by : Beth Ann Plattner
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:
Book Synopsis Studies Toward the Enantioselective Total Synthesis of the Martinella Alkaloids by : Vivek Badarinarayana
Download or read book Studies Toward the Enantioselective Total Synthesis of the Martinella Alkaloids written by Vivek Badarinarayana and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation consists of two parts. The first part describes the enantioselective total synthesis of martinellic acid. The Martinella alkaloids have attracted considerable attention in the synthetic community over the past few years. This interest is due in large part to their unique structure and useful biological activity (bradykinin receptor antagonist). In model systems we have successfully used the [3+2] azomethine ylide-alkene cycloaddition to construct the heterocyclic core of these alkaloids. The enantioselective approach described herein also involves the azomethine ylide-alkene cycloaddition as a key step in the total synthesis. The pyrrolo[3,2-c]quinoline core of this alkaloid was constructed in an enantioselective fashion by the elaboration of an N-aryl pyrrolidinone, which was obtained via Pd-catalyzed aryl amination reaction using a non-racemic lactam. Pirkle's chiral solvating agent was successfully used to demonstrate the stereochemical integrity of not only the N-aryl lactam (obtained by Pd-catalyzed cross-coupling) but also the cycloaddition precursor and the cycloaddition product (tetracyclic pyrroloquinoline core). The tetracyclic compound obtained via the azomethine ylide-alkene cycloaddition was elaborated to ( - )-martinellic acid in 11 steps and 6% overall yield. The second part of this dissertation describes application of several novel organometallic complexes for carrying out various organic transformations. A fluorinated tris(pyrazolyl)borato silver(I) complex catalyzes the addition of ethyl diazoacetate to benzene rings, providing norcaradienes, which undergo electrocyclization to provide the corresponding cycloheptatriene (the Bu & huml;chner reaction). These reactions are surprisingly selective for addition to the aromatic moiety rather than C-H insertion. A copper complex containing a fluorinated triazapentadienyl ligand has been used to catalyze some carbene and nitrene addition and insertion chemistry. Nitrene addition occurs rapidly and with both aryl and alkyl substituted olefins providing the corresponding aziridine. The carbene transfer reactions that were attempted include C-H insertion, O-H insertion and N-H insertion, of which the latter two were very efficient.
Book Synopsis Studies Directed Towards the Enantioselective Total Synthesis of Trans-Dihydrolycorcidine by : William L. Brown
Download or read book Studies Directed Towards the Enantioselective Total Synthesis of Trans-Dihydrolycorcidine written by William L. Brown and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Synthesis of Cyathin A3 by :
Download or read book Enantioselective Total Synthesis of Cyathin A3 written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2002 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies Toward an Enantioselective Total Synthesis of (-)- Aleurodiscal by : Todd M. Heidelbaugh
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:
