scholarly journals Synthesis of the Core Framework of the Cornexistins by Intramolecular Nozaki-Hiyama-Kishi Coupling

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2654
Author(s):  
Anthony Aimon ◽  
Louis J. Farrugia ◽  
J. Stephen Clark
Keyword(s):  
Natural Products ◽  
Direct Approach ◽  
Allylic Alcohols ◽  
Relative Configuration ◽  
The Core ◽  
Core Framework

A new and direct approach to the construction of the core framework of the herbicidal natural products cornexistin and hydroxycornexistin has been developed. Formation of the nine-membered carbocycle found in the natural products has been accomplished by an intramolecular Nozaki-Hiyama-Kishi reaction between a vinylic iodide and an aldehyde. Good yields of carbocyclic products were obtained from the reaction, but diastereomeric mixtures of allylic alcohols were produced. The cyclisation reaction was successful irrespective of the relative configuration of the stereogenic centres in the cyclisation precursor.

scholarly journals Synthesis of the tetracyclic core of Illicium sesquiterpenes using an organocatalyzed asymmetric Robinson annulation

2013 ◽  
Vol 9 ◽  
pp. 1135-1140 ◽  
Author(s):  
Lynnie Trzoss ◽  
Jing Xu ◽  
Michelle H Lacoske ◽  
Emmanuel A Theodorakis
Keyword(s):  
Natural Products ◽  
Neurodegenerative Diseases ◽  
Therapeutic Potential ◽  
Enantioselective Synthesis ◽  
Diversity Oriented Synthesis ◽  
Efficient Approach ◽  
The Core ◽  
Tetracyclic Core ◽  
Robinson Annulation ◽  
Core Framework

An enantioselective synthesis of the core framework of neurotrophic Illicium majucin-type sesquiterpenes is described here. This strategy is based on an organocatalyzed asymmetric Robinson annulation and provides an efficient approach for a diversity-oriented synthesis of Illicium natural products that holds remarkable therapeutic potential for neurodegenerative diseases.

scholarly journals Preparation of Cyclic Peptide Alkaloids Containing Functionalized Tryptophan Residues

2006 ◽  
Vol 1 (10) ◽  
pp. 1934578X0600101
Author(s):  
Alexander K. L. Yuen ◽  
Craig A. Hutton
Keyword(s):  
Natural Products ◽  
Cyclic Peptide ◽  
The Novel ◽  
Diazonamide A ◽  
The Core ◽  
Tryptophan Residues ◽  
Novel Methods

This review covers the synthesis of various cyclic peptide natural products possessing highly functionalized tryptophan residues, focusing on the examples of diazonamide A, the TMC-95 compounds, the celogentin/moroidin family and the complestatin/chloropeptin system. Recent efforts toward the preparation of these modified-tryptophan-containing peptides will be outlined, focusing primarily on the novel methods for the assembly of the highly functionalized indole/tryptophan moieties at the core of these structures.

scholarly journals Intramolecular cascade annulation triggered by rhodium(III)-catalyzed sequential C(sp2)–H activation and C(sp3)–H amination

2019 ◽  
Vol 15 ◽  
pp. 571-576 ◽  
Author(s):  
Liangliang Song ◽  
Guilong Tian ◽  
Johan Van der Eycken ◽  
Erik V Van der Eycken
Keyword(s):  
Natural Products ◽  
Functional Group ◽  
The Core

A rhodium(III)-catalyzed intramolecular oxidative annulation of O-substituted N-hydroxyacrylamides for the construction of indolizinones via sequential C(sp2)–H activation and C(sp3)–H amination has been developed. This approach shows excellent functional-group tolerance. The synthesized scaffold forms the core of many natural products with pharmacological relevance.

Stereodivergent synthesis of 1,4-dicarbonyls by traceless charge–accelerated sulfonium rearrangement

Science ◽  
2018 ◽  
Vol 361 (6403) ◽  
pp. 664-667 ◽  
Author(s):  
Dainis Kaldre ◽  
Immo Klose ◽  
Nuno Maulide
Keyword(s):  
Natural Products ◽  
Double Bond ◽  
Carbonyl Group ◽  
Organic Synthesis ◽  
Relative Configuration ◽  
Chiral Induction ◽  
Tremendous Importance ◽  
Acid Catalyzed ◽  
Quaternary Stereocenters ◽  
Drug Scaffolds

The chemistry of the carbonyl group is essential to modern organic synthesis. The preparation of substituted, enantioenriched 1,3- or 1,5-dicarbonyls is well developed, as their disconnection naturally follows from the intrinsic polarity of the carbonyl group. By contrast, a general enantioselective access to quaternary stereocenters in acyclic 1,4-dicarbonyl systems remains an unresolved problem, despite the tremendous importance of 2,3-substituted 1,4-dicarbonyl motifs in natural products and drug scaffolds. Here we present a broad enantioselective and stereodivergent strategy to access acyclic, polysubstituted 1,4-dicarbonyls via acid-catalyzed [3,3]-sulfonium rearrangement starting from vinyl sulfoxides and ynamides. The stereochemistry at sulfur governs the absolute sense of chiral induction, whereas the double bond geometry dictates the relative configuration of the final products.

scholarly journals Recent Advances in Organocatalyzed Asymmetric Synthesis of Benzopyran and Benzodihydropyran (Chromane) Nuclei

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1510
Author(s):  
Renato Dalpozzo ◽  
Raffaella Mancuso
Keyword(s):  
Natural Products ◽  
Asymmetric Synthesis ◽  
Organic Synthesis ◽  
Building Blocks ◽  
Core Structure ◽  
The Core ◽  
Recent Advances ◽  
Set Up

Benzopyran and benzodihydropyran (chromane) nuclei are the core structure of many natural products, in particular flavonoids. Many compounds possessing this structure are nutraceuticals, pharmaceutical nutrients. Therefore, benzopyran and chromane scaffolds are important building blocks in organic synthesis and many efforts have been made to set up efficient methods for their synthesis. In particular, asymmetric methods are of great importance, being natural products, and generally chiral substances. This review aims to cover literature in the range 2017–first half of 2019.

Synthesis of the core framework of the proposed structure of sargafuran

2013 ◽  
Vol 54 (4) ◽  
pp. 347-350 ◽  
Author(s):  
Ryo Katsuta ◽  
Kazuya Aoki ◽  
Arata Yajima ◽  
Tomoo Nukada
Keyword(s):  
The Core ◽  
Core Framework

scholarly journals Total synthesis and structural elucidation of natural products: (–)-Delactonmycin, (+)-plumerinine, and (–)-parvistemoamide

2005 ◽  
Vol 77 (7) ◽  
pp. 1153-1160 ◽  
Author(s):  
Ronaldo A. Pilli ◽  
Ivan R. Corrêa ◽  
Adriano O. Maldaner ◽  
Giovanni B. Rosso
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Inhibitory Activity ◽  
Structural Elucidation ◽  
Relative Configuration ◽  
Synthetic Studies ◽  
Hiv 1 ◽  
Rev Protein

Synthetic studies that established the relative configuration of (–)-delactonmycin, a polyketide with inhibitory activity against HIV-1 Rev protein, and our efforts toward the structural elucidation of the alkaloids (+)-plumerinine, isolated from P. rubra, and (–)-parvistemoamide, isolated from S. parviflora, are discussed.

Research on MapReduce Task Dynamic Balancing Strategy Based on File Label

2014 ◽  
Vol 571-572 ◽  
pp. 17-21
Author(s):  
Rong Huang ◽  
An Ping Xiong ◽  
Yang Zou
Keyword(s):  
Execution Time ◽  
Task Assignment ◽  
Total Execution Time ◽  
Dynamic Balancing ◽  
Processing Efficiency ◽  
The Core ◽  
Different Types ◽  
Assignment Strategy ◽  
Computing Performance ◽  
Core Framework

MapReduce is one of the core framework of Hadoop, it’s computing performance has been widely concerned and researched. In heterogeneous environment, unreasonable map task assignments and inefficient resource utilization lead to multiple backup tasks and the job total execution time is poor.For these problems, this paper proposes a new map task assignment strategy, which is map task dynamic balancing strategy based on file label. The strategy marks on job according to the different types, estimates node computing capabilities and historical processing efficiency of each label task, ensures map task which was assigned can execute successfully. Experiments show that, the strategy can effectively reduce number of backup tasks in map phase, and to some extent optimize the total execution time of the job.

scholarly journals The Structure of EMDR Therapy: A Guide for the Therapist

2021 ◽  
Vol 12 ◽  
Author(s):  
Michael Hase
Keyword(s):  
Best Practices ◽  
Therapeutic Relationship ◽  
Clinical Applications ◽  
Clinical Experiences ◽  
Core Element ◽  
The Core ◽  
Core Elements ◽  
Positive Treatment ◽  
Emdr Therapy ◽  
Core Framework

Since the introduction of EMD by Dr. Shapiro in 1987, which led to the development of EMDR Therapy, clinical experiences and research contributed to a variety of protocols and procedures. While this dynamic evolution within EMDR Therapy is offering more options to treat a variety of patients suffering from various disorders, there is a greater risk of deviations from the core framework of this approach that would no longer be understood as EMDR Therapy. While research shows that following Shapiro’s standard protocols and procedural steps is important to achieve positive treatment effects, it seems prudent to define the core elements in EMDR Therapy beyond adherence to the standard protocol given the complexity of clinical demands in a variety of treatment contexts. The author proposes that best practices requires not only an adherence to the fidelity of the model, but a willingness to adapt the model in order to best meet the needs of our clients in a variety of clinical contexts. Defining the core elements that constitute EMDR Therapy offers both a structure that has been well established and offers a foundation from which clinical adaptations can be made that are within the realm of what is widely accepted as EMDR Therapy. Such a structure could also be used to define research as well as clinical applications. Additionally EMDR Therapy as a comprehensive psychotherapy approach implies that the therapeutic relationship is an important component and should be considered a core element of this methodology.

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