Toward the Synthesis of the Magellaninone- and Lycopladine-type Lycopodium Alkaloids

Toward the Synthesis of the Magellaninone- and Lycopladine-type Lycopodium Alkaloids PDF Author: Rebecca Anne Murphy
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Category :
Languages : en
Pages : 340

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This dissertation describes our strategy toward the synthesis of a variety of fawcettimine-type Lycopodium alkaloids. The first section focuses on the classification, structure, and historical significance of these natural products. This section also includes a proposal for their biosynthesis and a survey of the biological activities of the members of this class. The second section describes our work toward magellanine, magellaninone, and paniculatine. Two existing syntheses of these molecules are discussed, along with the strategy that we chose to employ in our work. We first pursue the synthesis of these natural products using a C4 pyridine C-H functionalization strategy that is based on precedent by the Fagnou and Echavarren groups. We then describe a C3 pyridine C-H functionalization approach that has more diverse methodological inspiration, although the original synthetic disconnection strategy derives from work done by the Jin Quan Yu group. Both of these synthetic endeavors are detailed herein. Finally, the third section covers our efforts toward the synthesis of lycopladines B, C, and D. We describe our "Heathcock-inspired"cascade approach toward the divergent synthesis of these three natural products. In this work, we have pursued the synthesis of a number of different substrates. We conclude with a summary of how this approach has evolved into a number of other projects within our group.

Toward the Synthesis of the Magellaninone- and Lycopladine-type Lycopodium Alkaloids

Toward the Synthesis of the Magellaninone- and Lycopladine-type Lycopodium Alkaloids PDF Author: Rebecca Anne Murphy
Publisher:
ISBN:
Category :
Languages : en
Pages : 340

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Book Description
This dissertation describes our strategy toward the synthesis of a variety of fawcettimine-type Lycopodium alkaloids. The first section focuses on the classification, structure, and historical significance of these natural products. This section also includes a proposal for their biosynthesis and a survey of the biological activities of the members of this class. The second section describes our work toward magellanine, magellaninone, and paniculatine. Two existing syntheses of these molecules are discussed, along with the strategy that we chose to employ in our work. We first pursue the synthesis of these natural products using a C4 pyridine C-H functionalization strategy that is based on precedent by the Fagnou and Echavarren groups. We then describe a C3 pyridine C-H functionalization approach that has more diverse methodological inspiration, although the original synthetic disconnection strategy derives from work done by the Jin Quan Yu group. Both of these synthetic endeavors are detailed herein. Finally, the third section covers our efforts toward the synthesis of lycopladines B, C, and D. We describe our "Heathcock-inspired"cascade approach toward the divergent synthesis of these three natural products. In this work, we have pursued the synthesis of a number of different substrates. We conclude with a summary of how this approach has evolved into a number of other projects within our group.

Studies Directed Toward the Total Synthesis of the Magellanane Class of the Lycopodium Alkaloids

Studies Directed Toward the Total Synthesis of the Magellanane Class of the Lycopodium Alkaloids PDF Author: Paul Steven Watson
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ISBN:
Category : Alkaloids
Languages : en
Pages : 372

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A Biogenetic Approach to the Synthesis of the Lycopodium Alkaloids

A Biogenetic Approach to the Synthesis of the Lycopodium Alkaloids PDF Author: Gregory Wayne Schwing
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Category :
Languages : en
Pages : 140

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Part I - Synthesis of the Tetracyclic Skeleton of the Lycopodium Alkaloid Lycopladine Hpart Ii - Synthesis of the Tetracyclic Core of the Apparicine Class of Indole Alkaloids Via a Key Intermolecular Nitrosoalkene Conjugate Addition

Part I - Synthesis of the Tetracyclic Skeleton of the Lycopodium Alkaloid Lycopladine Hpart Ii - Synthesis of the Tetracyclic Core of the Apparicine Class of Indole Alkaloids Via a Key Intermolecular Nitrosoalkene Conjugate Addition PDF Author: Pradeep Chauhan
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ISBN:
Category :
Languages : en
Pages :

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AbstractPart IA synthesis of the tetracyclic framework 220 of the structurally unique Lycopodium alkaloid lycopladine H (21) has been achieved in 19 steps from phenol 60. A key step involved a novel double alkene hydroformylation/intramolecular reductive amination of 217 to form the azocane and spiropiperidine moieties of the natural product in the form of advanced tetracyclic intermediate 220 via intermediate dialdehyde 218. Disappointingly, we have been unable to convert this compound into the natural product. Part IIA convergent and concise synthetic route to the tetracyclic core 61 of the apparicine-type alkaloids has been achieved in only four steps in 80% overall yield from the known 3-formylindole ester 113 and 3-piperidone-derived [alpha]-chloroketoxime 80. Key transformations involve use of an intermolecular ester enolate/nitrosoalkene conjugate addition to form the C-15/16 bond of 117, followed by a reductive cyclization to form the C-ring of the tetracycle core 61, which has appropriate handles in place at C-16 and C-20, to easily access a number of the members of the apparicine class of indole alkaloids.

Synthesis of Lycodine-Type Lycopodium Alkaloids Using C-H Functionalization Tactics

Synthesis of Lycodine-Type Lycopodium Alkaloids Using C-H Functionalization Tactics PDF Author: James Newton
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ISBN:
Category :
Languages : en
Pages : 97

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This dissertation describes our syntheses of several lycodine-type Lycopodium alkaloids by the late-stage C-H functionalization of lycodine derivatives. Lycodine-type alkaloids are well-known for their neurological activity. For example, huperzine A is a potent acetylcholinesterase inhibitor and the complanadine family of molecules has been shown to induce the secretion of Nerve Growth Factor. Due to these properties, lycodine-type alkaloids serve as interesting lead compounds for the development of new therapies for neurodegenerative disorders, such as Alzheimer's disease. Unsurprisingly, these molecules have attracted the attention of the synthetic community. Chapter 1 reviews syntheses of lycodine-type Lycopodium alkaloids with particular emphasis on the syntheses of biologically active congeners. Chapter 2 describes our synthesis of complanadine B, an unsymmetrical dimer of lycodine, using two approaches. In the first, the requisite skeletal oxygenation was installed early in the synthetic sequence. Our second approach utilized a blocking group strategy to enable the late-stage oxygenation of the complanadine skeleton by preventing oxygenation at undesired sites. Chapter 3 describes our efforts toward the synthesis of the casuarinine family of Lycopodium alkaloids by the late-stage C-H functionalization of lycodine derivatives. Using this strategy, we have been able to complete the synthesis of casuarinine D and have made significant progress toward the synthesis of casuarinine H, which we believe can serve as an intermediate in the synthesis of several other lycodine-type alkaloids.

Unified Approach to the Lycodine Lycopodium Alkaloids

Unified Approach to the Lycodine Lycopodium Alkaloids PDF Author: Michael David Purdham
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ISBN:
Category :
Languages : en
Pages : 198

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A Unified Approach Toward the Total Synthesis of Lycopodium Alkaloids of the Miscellaneous Class

A Unified Approach Toward the Total Synthesis of Lycopodium Alkaloids of the Miscellaneous Class PDF Author: Sarah Elizabeth House
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ISBN:
Category :
Languages : en
Pages : 370

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A unified approach to the total synthesis of Lycopodium alkaloids belonging to the miscellaneous class has been developed, wherein a single tetracyclic amine is employed as a common intermediate in synthetic studies toward several alkaloids. An overview of Lycopodium alkaloids is presented, including their structural classification, isolation and biological activity. The biosynthesis of alkaloids in the miscellaneous group is discussed in depth. A summary of previous synthetic work focusing on miscellaneous Lycopodium alkaloids is presented, including total syntheses of luciduline, lyconadins A and B and nankakurines A and B.A model study of spirolucidine is discussed. A biomimetic route to access spirolucidine and nankakurine B has been investigated. In this study, a tetracyclic amine that is a key intermedite in the total synthesis of lyconadin A previously developed in our laboratory is elaborated into a tertiary alcohol that mimics the proposed biosynthetic precursor of nankakurine B.A biomimetic ring-contractive [alpha]-hydroxyimine rearrangement to generate nankakurine B has been extensively investigated and found to be disfavored. The conversion of a tricyclic ketone (first synthesized en route to lyconadin A) to the tetracyclic core of serratezomine D has been investigated. The core of this molecule was inaccessible via methods employed in the studies toward lyconadin A. The total synthesis of 1'-epi-dihydrolycolucine from the key common tetracyclic amine intermediate has been achieved. Studies toward the synthesis of serratezomine E served as a platform to develop this method and to determine the stereochemical outcome of this reaction.

An Approach to the Synthesis of Lycopodium Alkaloids

An Approach to the Synthesis of Lycopodium Alkaloids PDF Author: Friedrich K. Hess
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Category : Alkaloids
Languages : en
Pages : 0

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Approaches to the Total Synthesis of the Lycopodium Alkaloid Fawcettimine and Related Studies

Approaches to the Total Synthesis of the Lycopodium Alkaloid Fawcettimine and Related Studies PDF Author: Todd Andrew Blumenkopf
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ISBN:
Category :
Languages : en
Pages : 648

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Lycopodium Alkaloids

Lycopodium Alkaloids PDF Author: Jerold Steven Horn
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ISBN:
Category : Alkaloids
Languages : en
Pages : 150

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