Enantioselective Syntheses of Yohimbine Alkaloids: Proving Grounds for New Catalytic Transformations

Synthesis ◽  
2021 ◽  
Author(s):  
Karl A. Scheidt ◽  
Eric R Miller
Keyword(s):  
Natural Products ◽  
Chemical Synthesis ◽  
Total Synthesis ◽  
State Of The Art ◽  
The State ◽  
Catalytic Transformations ◽  
Bond Forming ◽  
The Past ◽  
Catalytic Asymmetric ◽  
Enantioselective Syntheses

The total synthesis of bioactive alkaloids is an enduring challenge and an indication of the state of the art of chemical synthesis. With the explosion of catalytic asymmetric methods over the past three decades, these compelling targets have been fertile proving grounds for enantioselective bond forming transformations. We summarize these activities herein both to highlight the power and versatility of these methods and to instill future inspiration for new syntheses of these privileged natural products.

Catalytic asymmetric preparation of pyrroloindolines: strategies and applications to total synthesis

2021 ◽  
Author(s):  
Guang-Jian Mei ◽  
Wai Lean Koay ◽  
Chuan Xiang Alvin Tan ◽  
Yixin Lu
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
State Of The Art ◽  
Catalytic Asymmetric Synthesis ◽  
Catalytic Asymmetric

Pyrroloindolines are widely present in natural products. In this review, we summarize state-of-the-art of catalytic asymmetric synthesis of pyrroloindolines, as well as related applications to natural products total synthesis.

Ester coupling reactions – an enduring challenge in the chemical synthesis of bioactive natural products

2015 ◽  
Vol 32 (4) ◽  
pp. 605-632 ◽  
Author(s):  
Michail Tsakos ◽  
Eva S. Schaffert ◽  
Lise L. Clement ◽  
Nikolaj L. Villadsen ◽  
Thomas B. Poulsen
Keyword(s):  
Natural Products ◽  
Chemical Synthesis ◽  
Natural Product ◽  
Organic Synthesis ◽  
State Of The Art ◽  
The State ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Bioactive Natural Products ◽  
Complex Ester

In this review we investigate the use of complex ester fragment couplings within natural product total syntheses. Using examples from the literature up to 2014 we illustrate the state-of-the-art as well as the challenges within this area of organic synthesis.

scholarly journals Unified divergent strategy towards the total synthesis of the three sub-classes of hasubanan alkaloids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guang Li ◽  
Qian Wang ◽  
Jieping Zhu
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Total Syntheses ◽  
Bond Forming ◽  
The Past ◽  
Tricyclic Compounds

AbstractElegant asymmetric synthesis of hasubanan alkaloids have been developed over the past decades. However, a divergent approach leading to all three sub-classes of this family of natural products remains unknown. We report herein the realization of such an endeavor by accomplishing enantioselective total syntheses of four representative members. The synthesis is characterized by catalytic enantioselective construction of the tricyclic compounds from which three different intramolecular C-N bond forming processes leading to three topologically different hasubanan alkaloids are developed. An aza-Michael addition is used for the construction of the aza-[4.4.3]-propellane structure of (-)-cepharamine, whereas an oxidation/double deprotection/intramolecular hemiaminal forming sequence is developed to forge the bridged 6/6/6/6 tetracycle of (-)-cepharatines A and C and a domino bromination/double deprotection/cyclization sequence allows the build-up of the 6/6/5/5 fused tetracyclic structure of (−)-sinoracutine.

scholarly journals Modern Synthetic Methods for the Stereoselective Construction of 1,3-Dienes

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 249
Author(s):  
Raquel G. Soengas ◽  
Humberto Rodríguez-Solla
Keyword(s):  
Organic Chemistry ◽  
Natural Products ◽  
Functional Group ◽  
Biological Activities ◽  
Synthetic Methods ◽  
Bond Forming ◽  
Drug Candidates ◽  
The Past ◽  
Wide Range

The 1,3-butadiene motif is widely found in many natural products and drug candidates with relevant biological activities. Moreover, dienes are important targets for synthetic chemists, due to their ability to give access to a wide range of functional group transformations, including a broad range of C-C bond-forming processes. Therefore, the stereoselective preparation of dienes have attracted much attention over the past decades, and the search for new synthetic protocols continues unabated. The aim of this review is to give an overview of the diverse methodologies that have emerged in the last decade, with a focus on the synthetic processes that meet the requirements of efficiency and sustainability of modern organic chemistry.

scholarly journals The state of the art in soybean transcriptomics resources and gene coexpression networks

2021 ◽  
Author(s):  
Fabricio Almeida-Silva ◽  
Kanhu C Moharana ◽  
Thiago M Venancio
Keyword(s):  
State Of The Art ◽  
The State ◽  
Gene Coexpression Network ◽  
Rna Seq ◽  
Transcriptomic Data ◽  
The Past ◽  
Gene Coexpression ◽  
Genomics Research ◽  
Public Repositories ◽  
Coexpression Networks

Abstract In the past decade, over 3000 samples of soybean transcriptomic data have accumulated in public repositories. Here, we review the state of the art in soybean transcriptomics, highlighting the major microarray and RNA-seq studies that investigated soybean transcriptional programs in different tissues and conditions. Further, we propose approaches for integrating such big data using gene coexpression network and outline important web resources that may facilitate soybean data acquisition and analysis, contributing to the acceleration of soybean breeding and functional genomics research.

The State of the Art in Management Education Applicable to Aerospace Activities

1967 ◽  
Vol 71 (677) ◽  
pp. 342-343
Author(s):  
F. H. East
Keyword(s):  
Research And Development ◽  
Management Education ◽  
State Of The Art ◽  
Development Project ◽  
The State ◽  
The Other ◽  
The Past ◽  
Defence Budget ◽  
The One ◽  
Almost All

The Aviation Group of the Ministry of Technology (formerly the Ministry of Aviation) is responsible for spending a large part of the country's defence budget, both in research and development on the one hand and production or procurement on the other. In addition, it has responsibilities in many non-defence fields, mainly, but not exclusively, in aerospace.Few developments have been carried out entirely within the Ministry's own Establishments; almost all have required continuous co-operation between the Ministry and Industry. In the past the methods of management and collaboration and the relative responsibilities of the Ministry and Industry have varied with time, with the type of equipment to be developed, with the size of the development project and so on. But over the past ten years there has been a growing awareness of the need to put some system into the complex business of translating a requirement into a specification and a specification into a product within reasonable bounds of time and cost.

Cultural Economics: The State of the Art and Perspectives

2021 ◽  
Vol 27 (1) ◽  
pp. 7-32
Author(s):  
Bruce A. Seaman
Keyword(s):  
Industrial Organization ◽  
Intellectual Development ◽  
State Of The Art ◽  
Cultural Economics ◽  
The State ◽  
Sports Economics ◽  
Developmental Patterns ◽  
The Past ◽  
Alternative Perspective ◽  
Core Questions

The intellectual development of cultural economics has exhibited some notable similarities to the challenges faced by researchers pioneering in other areas of economics. While this is not really surprising, previous reviews of this literature have not focused on such patterns. Specifically, the methodology and normative implications of the field of industrial organization and antitrust policy suggest a series of stages identified here as foundation, maturation, reevaluation, and backlash that suggest a way of viewing the development of and controversies surrounding cultural economics. Also, the emerging field of sports economics, which already shares some substantive similarities to the questions addressed in cultural economics, presents a pattern of development by which core questions and principles are identified in a fragmented literature, which then slowly coalesces and becomes consolidated into a more unified literature that essentially reconfirms and extends those earlier core principles. This fragmentation and consolidation pattern is also exhibited by the development of cultural economics. While others could surely suggest different parallels in the search for such developmental patterns, this way of organizing ones thinking about the past and future of this field provides a hoped for alternative perspective on the state of the art of cultural economics.

scholarly journals 3D Printing in Heterogeneous Catalysis—The State of the Art

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4534 ◽  
Author(s):  
Elżbieta Bogdan ◽  
Piotr Michorczyk
Keyword(s):  
Additive Manufacturing ◽  
Heterogeneous Catalysis ◽  
3D Printing ◽  
Chemical Synthesis ◽  
State Of The Art ◽  
Three Dimensional ◽  
Production Method ◽  
The State ◽  
Monolithic Catalysts ◽  
Selection Of

This paper describes the process of additive manufacturing and a selection of three-dimensional (3D) printing methods which have applications in chemical synthesis, specifically for the production of monolithic catalysts. A review was conducted on reference literature for 3D printing applications in the field of catalysis. It was proven that 3D printing is a promising production method for catalysts.

scholarly journals The Embeddedness of Social Sciences and Economics in Research on Resources

Resources ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 15
Author(s):  
Juan Uribe-Toril ◽  
José Luis Ruiz-Real ◽  
Jaime de Pablo Valenciano
Keyword(s):  
Social Sciences ◽  
State Of The Art ◽  
Local Development ◽  
The State ◽  
Special Issue ◽  
Continuous Review ◽  
The Past ◽  
Research Fields ◽  
Wide Range ◽  
Knowledge Area

Sustainability, local development, and ecology are keywords that cover a wide range of research fields in both experimental and social sciences. The transversal nature of this knowledge area creates synergies but also divergences, making a continuous review of the existing literature necessary in order to facilitate research. There has been an increasing number of articles that have analyzed trends in the literature and the state-of-the-art in many subjects. In this Special Issue of Resources, the most prestigious researchers analyzed the past and future of Social Sciences in Resources from an economic, social, and environmental perspective.

scholarly journals Complex Data Imputation by Auto-Encoders and Convolutional Neural Networks—A Case Study on Genome Gap-Filling

Computers ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 37 ◽  
Author(s):  
Luca Cappelletti ◽  
Tommaso Fontana ◽  
Guido Walter Di Donato ◽  
Lorenzo Di Tucci ◽  
Elena Casiraghi ◽  
...  
Keyword(s):  
Deep Learning ◽  
Missing Data ◽  
State Of The Art ◽  
The State ◽  
Complex Data ◽  
Data Imputation ◽  
Genome Sequences ◽  
Missing Data Imputation ◽  
The Past ◽  
Learning Techniques

Missing data imputation has been a hot topic in the past decade, and many state-of-the-art works have been presented to propose novel, interesting solutions that have been applied in a variety of fields. In the past decade, the successful results achieved by deep learning techniques have opened the way to their application for solving difficult problems where human skill is not able to provide a reliable solution. Not surprisingly, some deep learners, mainly exploiting encoder-decoder architectures, have also been designed and applied to the task of missing data imputation. However, most of the proposed imputation techniques have not been designed to tackle “complex data”, that is high dimensional data belonging to datasets with huge cardinality and describing complex problems. Precisely, they often need critical parameters to be manually set or exploit complex architecture and/or training phases that make their computational load impracticable. In this paper, after clustering the state-of-the-art imputation techniques into three broad categories, we briefly review the most representative methods and then describe our data imputation proposals, which exploit deep learning techniques specifically designed to handle complex data. Comparative tests on genome sequences show that our deep learning imputers outperform the state-of-the-art KNN-imputation method when filling gaps in human genome sequences.

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