Author: Peter V. Zawada
Publisher:
ISBN:
Category :
Languages : en
Pages : 728
Book Description
Synthetic Studies Directed Towards the Total Synthesis of Penitrem D.
Author: Peter V. Zawada
Publisher:
ISBN:
Category :
Languages : en
Pages : 728
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 728
Book Description
Part A. Studies Directed Towards the Total Synthesis of (±) A-23187 ; Part B. Formal Total Synthesis of (±) A-23187
Author: Eric L. Williams
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 164
Book Description
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 164
Book Description
Synthetic Studies Towards the Total Synthesis of Lancifodilactone G.
Author: Sanil Sreekumar
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This thesis presents our studies towards the first total synthesis of the novel anti- HIV agent lancifodilactone G, which has a highly unusual aliphatic enol. The first chapter provides a survey of architecturally diverse nortriterpenoids that were isolated from the Schisandraceae family. A proposed biosynthetic pathway for lancifodilactone G and closely related natural products provides a rationale for the formation of the consecutive 7/8/5 fused carbo cycles that are unique to Schisandra nortriterpenoids. Chapter 1 goes on to outline the reported strategies to access the core of lancifodilactone G and concludes with a retrosynthetic analysis proposed by the Evans group, which includes a biosynthetically inspired single-pot polycyclisation reaction. Chapter 2 describes the highly stereocontrolled synthesis of the eastern fragment (F-G rings) using transition metal-mediated Pauson-Khand reaction. This chapter also reviews the metal-mediated diastereoselective Pauson-Khand reaction directed by the stereogenic centre at C2, with the ample illustration to total synthesis. Attempted strategies for the assembly of the bicyclic cyclopentanone motif via a dienyl Pauson-Khand reaction of silicon- and oxygen- tethered diene-enes are presented. The failure of these strategies at different stages of the synthesis resulted in the exploration of a classical Pauson-Khand approach, which successfully furnished the eastern fragment. Finally, a second-generation synthesis is described which provided the fully functionalised eastern fragment with improved efficiency and overall yield. Chapter 3 discusses the successful synthesis of the western fragment (B-C rings) using a diastereoselective [4+3] cycloaddition strategy. Attempted strategies for the synthesis of the key 2,3-disubstituted furan derivative are presented, which was achieved via a hetero Pauson- Khand reaction. This chapter includes a brief account of the classical [4+3] cycloaddition reactions of furans using an in situ generated oxyallyl cation and also employing vinyl carbenoids in the metal-catalysed version. The review also highlights the application of the [4+ 3] cycloaddition reaction in the expeditious assembly of functionalised 7-membered rings that occur in a number of important biologically active natural products. The third chapter goes on to describe the application of these cycloaddition reactions in the synthesis of the fully functionalised western fragment of Lancifodilactone G. Chapter 4 describes a model study aimed at expediting the synthesis of the western fragment using a rhodium-catalysed allylic substitution reaction. A brief mechanistic discussion on unique aspects of the allylic alkylation reaction is illustrated. Chapter 4 concludes by outlining the coupling strategy for eastern and western fragments and the end game studies for the completion of the synthesis of lancifodilactone G.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This thesis presents our studies towards the first total synthesis of the novel anti- HIV agent lancifodilactone G, which has a highly unusual aliphatic enol. The first chapter provides a survey of architecturally diverse nortriterpenoids that were isolated from the Schisandraceae family. A proposed biosynthetic pathway for lancifodilactone G and closely related natural products provides a rationale for the formation of the consecutive 7/8/5 fused carbo cycles that are unique to Schisandra nortriterpenoids. Chapter 1 goes on to outline the reported strategies to access the core of lancifodilactone G and concludes with a retrosynthetic analysis proposed by the Evans group, which includes a biosynthetically inspired single-pot polycyclisation reaction. Chapter 2 describes the highly stereocontrolled synthesis of the eastern fragment (F-G rings) using transition metal-mediated Pauson-Khand reaction. This chapter also reviews the metal-mediated diastereoselective Pauson-Khand reaction directed by the stereogenic centre at C2, with the ample illustration to total synthesis. Attempted strategies for the assembly of the bicyclic cyclopentanone motif via a dienyl Pauson-Khand reaction of silicon- and oxygen- tethered diene-enes are presented. The failure of these strategies at different stages of the synthesis resulted in the exploration of a classical Pauson-Khand approach, which successfully furnished the eastern fragment. Finally, a second-generation synthesis is described which provided the fully functionalised eastern fragment with improved efficiency and overall yield. Chapter 3 discusses the successful synthesis of the western fragment (B-C rings) using a diastereoselective [4+3] cycloaddition strategy. Attempted strategies for the synthesis of the key 2,3-disubstituted furan derivative are presented, which was achieved via a hetero Pauson- Khand reaction. This chapter includes a brief account of the classical [4+3] cycloaddition reactions of furans using an in situ generated oxyallyl cation and also employing vinyl carbenoids in the metal-catalysed version. The review also highlights the application of the [4+ 3] cycloaddition reaction in the expeditious assembly of functionalised 7-membered rings that occur in a number of important biologically active natural products. The third chapter goes on to describe the application of these cycloaddition reactions in the synthesis of the fully functionalised western fragment of Lancifodilactone G. Chapter 4 describes a model study aimed at expediting the synthesis of the western fragment using a rhodium-catalysed allylic substitution reaction. A brief mechanistic discussion on unique aspects of the allylic alkylation reaction is illustrated. Chapter 4 concludes by outlining the coupling strategy for eastern and western fragments and the end game studies for the completion of the synthesis of lancifodilactone G.
Studies Directed Towards the Total Synthesis of Papulacandin D
Author: Jon Adam Willardsen
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 74
Book Description
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 74
Book Description
Synthetic Studies
Author: Qiang Han
Publisher:
ISBN:
Category :
Languages : en
Pages : 286
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 286
Book Description
Synthetic Efforts Directed Towards the Total Synthesis of the Polycyclic Natural Products N-methylwelwistatin and Communesin B
Author: Seth L. Crawley
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
American Doctoral Dissertations
Author:
Publisher:
ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 776
Book Description
Publisher:
ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 776
Book Description
Synthetic Studies on Biologically Interesting Molecules
Author: Jason Daniel Speake
Publisher:
ISBN:
Category :
Languages : en
Pages : 316
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 316
Book Description
Total Synthesis of Plakortide E and Biomimetic Synthesis of Plakortone B
Author: Xiao-Yu Sun
Publisher: Springer Science & Business Media
ISBN: 3642271952
Category : Science
Languages : en
Pages : 232
Book Description
In his thesis, Xiaoyu Sun conducts the first total synthesis of all possible stereoisomers of plakortide E and also confirms the absolute configuration of natural plakortide E. Xiaoyu Sun subsequently converts Plakortide E methyl ester to plakortone B in a biomimetic conversion. Construction and functionalization of cyclic peroxides are notoriously difficult due to the very low O-O bond dissociation energy. Plaktoride E is isolated from the Jamaican marine sponge platorits halichondrioides and contains a five-membered peroxide ring, with oxygen atoms linked to tertiary C4 and C6 centers. The methodology used for synthesizing highly substituted cyclic peroxides is novel and useful, and not only extends the field of Pd-catalyzed reactions, but also provides a convenient synthetic approach for the preparation of the 1,2-dioxolanes series. Plakortide E and plakortone B are bioactive, which means that the synthetic studies on them and their analogs are pivotal in drug discovery.
Publisher: Springer Science & Business Media
ISBN: 3642271952
Category : Science
Languages : en
Pages : 232
Book Description
In his thesis, Xiaoyu Sun conducts the first total synthesis of all possible stereoisomers of plakortide E and also confirms the absolute configuration of natural plakortide E. Xiaoyu Sun subsequently converts Plakortide E methyl ester to plakortone B in a biomimetic conversion. Construction and functionalization of cyclic peroxides are notoriously difficult due to the very low O-O bond dissociation energy. Plaktoride E is isolated from the Jamaican marine sponge platorits halichondrioides and contains a five-membered peroxide ring, with oxygen atoms linked to tertiary C4 and C6 centers. The methodology used for synthesizing highly substituted cyclic peroxides is novel and useful, and not only extends the field of Pd-catalyzed reactions, but also provides a convenient synthetic approach for the preparation of the 1,2-dioxolanes series. Plakortide E and plakortone B are bioactive, which means that the synthetic studies on them and their analogs are pivotal in drug discovery.
Synthesis Studies Directed Towards the Total Synthesis of (+)-trilobacin, (+)-trilobin and (+)-asitribin
Author: Michael John Mayer
Publisher:
ISBN:
Category :
Languages : en
Pages : 360
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 360
Book Description