Macrocyclization by Ring-Closing Metathesis in the Total Synthesis of Natural Products: Reaction Conditions and Limitations

2006 ◽  
Vol 45 (37) ◽  
pp. 6086-6101 ◽  
Author(s):  
Ana Gradillas ◽  
Javier Pérez-Castells
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Ring Closing Metathesis ◽  
Reaction Conditions

Natural products with taxol-like anti-tumor activity: Synthetic approaches to eleutherobin and dictyostatin

2007 ◽  
Vol 79 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Cesare Gennari ◽  
Damiano Castoldi ◽  
Ofer Sharon
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Cytotoxic Activity ◽  
Natural Product ◽  
Mode Of Action ◽  
Dynamic Instability ◽  
Ring System ◽  
Ring Closing Metathesis ◽  
Synthetic Approaches ◽  
Anti Tumor Activity

Eleutherobin and dictyostatin are antimitotic compounds which exert their cytotoxic activity by a taxol-like mode of action, i.e., hypernucleating tubulin assembly and interfering with the dynamic instability of the cytoskeleton during mitosis. A formal total synthesis of eleutherobin was accomplished by accessing a key intermediate reported by Danishefsky and coworkers in their 1998 synthesis of the natural product. The key step of our strategy, used for obtaining the [8.4.0] fused bicyclic ring system, is a ring-closing metathesis (RCM) reaction of a densely functionalized diene under forcing conditions, using Grubbs' second-generation catalyst. Synthetic approaches to dictyostatin are also described, and in particular the preparation of the C15-C23 fragment of the macrolide, containing 5 of its 11 stereocenters.

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Application of Dess-Martin oxidation in total synthesis of natural products

2020 ◽  
Vol 17 ◽  
Author(s):  
Majid M. Heravi ◽  
Tayebe Momeni ◽  
Vahideh Zadsirjan ◽  
Leila Mohammadi
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Selective Oxidation ◽  
Secondary Alcohols ◽  
Aldehydes And Ketones

: Dess–Martin periodinane (DMP), is a commercially available chemical, frequently being utilized as a mild oxidative agent for the selective oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. DMP shows several merits over other common oxidative agent such as chromium- and DMSO-based oxidants, thus it is habitually employed in the total synthesis of natural products. In this review, we try to underscore the applications of DMP as an effective oxidant in an appropriate step (steps) in the multistep total synthesis of natural products.

scholarly journals Non-Enzymatic Desymmetrization Reactions in Aqueous Media

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 720
Author(s):  
Satomi Niwayama
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Functional Groups ◽  
Organic Compounds ◽  
Recent Progress ◽  
Aqueous Media ◽  
Building Blocks ◽  
Organic Reactions ◽  
Environmentally Benign ◽  
Enzymatic Desymmetrization

Symmetric organic compounds are generally obtained inexpensively, and therefore they can be attractive building blocks for the total synthesis of various pharmaceuticals and natural products. The drawback is that discriminating the identical functional groups in the symmetric compounds is difficult. Water is the most environmentally benign and inexpensive solvent. However, successful organic reactions in water are rather limited due to the hydrophobicity of organic compounds in general. Therefore, desymmetrization reactions in aqueous media are expected to offer versatile strategies for the synthesis of a variety of significant organic compounds. This review focuses on the recent progress of desymmetrization reactions of symmetric organic compounds in aqueous media without utilizing enzymes.

Total synthesis: the structural confirmation of natural products

2021 ◽  
Vol 57 (27) ◽  
pp. 3307-3322
Author(s):  
Debobrata Paul ◽  
Ashis Kundu ◽  
Sanu Saha ◽  
Rajib Kumar Goswami
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Feature Article

This feature article highlights total synthesis as one of the reliable tools for the structural confirmation of natural products.

scholarly journals Applications of the Horner-Wadsworth-Emmons olefination in modern natural product synthesis

Synthesis ◽  
2021 ◽  
Author(s):  
Dávid Roman ◽  
Maria Sauer ◽  
Christine Beemelmanns
Keyword(s):  
Natural Products ◽  
Natural Product ◽  
Natural Product Synthesis ◽  
Reaction Conditions ◽  
Comprehensive Review ◽  
Modern Natural ◽  
Key Steps ◽  
Synthetic Approaches

Here, we have summarized more than 30 representative natural product syntheses published in 2015 to 2020 that employ one or more Horner-Wadsworth-Emmons (HWE) reactions. We comprehensively describe the applied phosphonate reagents, HWE reaction conditions and key steps of the total synthetic approaches. Our comprehensive review will support future synthetic approaches and serve as guideline to find the best HWE conditions for the most complicated natural products known

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