Related Experiment Video
Updated: Jul 17, 2026
09:26
Cellular Lipid Extraction for Targeted Stable Isotope Dilution Liquid Chromatography-Mass Spectrometry Analysis
Published on: November 17, 2011
Total synthesis of amphidinolide E
1Department of Chemistry, Scripps Florida, Jupiter, Florida 33458, USA.
Journal of the American Chemical Society
|December 15, 2006
Summary
Researchers achieved a stereocontrolled synthesis of amphidinolide E. This involved a highly diastereoselective [3+2] annulation reaction, yielding a key tetrahydrofuran intermediate.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Natural Product Synthesis
Background:
- Amphidinolide E is a marine macrolide with potential biological activity.
- Efficient and stereocontrolled synthesis of complex natural products is a significant challenge in organic chemistry.
Purpose of the Study:
- To develop a convergent and highly stereocontrolled synthetic route to amphidinolide E.
- To establish a key bond-forming reaction for the construction of the amphidinolide core.
Main Methods:
- A convergent synthetic strategy was employed.
- A key step involved a Lewis acid-promoted [3+2] annulation reaction between an aldehyde and an allylsilane.
- Boron trifluoride etherate (BF3.Et2O) was used as the Lewis acid catalyst.
Main Results:
- The synthesis of amphidinolide E (1) was successfully accomplished.
- The [3+2] annulation reaction proceeded with high diastereoselectivity (>20:1).
- A substituted tetrahydrofuran intermediate (2) was efficiently formed.
Conclusions:
- A practical and stereocontrolled synthesis of amphidinolide E has been developed.
- The employed [3+2] annulation strategy is effective for constructing complex cyclic systems.
- This synthesis provides access to amphidinolide E for further biological evaluation.
Related Concept Videos
01:23Complexation Equilibria: Overview
Complexation reactions take place when dative or coordinate covalent bonds form between metal ions and ligands. The compounds formed in these reactions are called coordination compounds. The number of bonds formed between the metal ion and the ligands is called its coordination number. Generally, most metal ions in an aqueous solution are solvated by water molecules and thus exist as aqua complexes.
The equilibrium constant of the complexation reaction is represented as the formation constant...
The equilibrium constant of the complexation reaction is represented as the formation constant...
01:19Composition of Polyprotic Acid Solutions as a Function of pH
Polyprotic acids of the type H2M constitute two ionizable protons. As a result, on titration with a base, they exhibit two equivalence points in the titration curve. During titration, the species H2M, HM−, and M2− will be present in the solution at different points. The fractions of H2M, HM−, and M2− present at the various instances of the titration are denoted by α0, α1, and α2, respectively.
A graph with the alpha values is plotted against the volume of base added during titration. Here, a...
A graph with the alpha values is plotted against the volume of base added during titration. Here, a...
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...
01:09EDTA: Conditional Formation Constant
Each EDTA molecule has six binding sites: four carboxyl groups and two amino groups. The fully protonated form of EDTA is represented as H6Y2+. However, it can exist in different forms, H5Y+, H4Y, H3Y−, H2Y2−, and HY3−, depending on the pH of the solution. In very basic solutions with pH > 10.17, the fully deprotonated form, Y4−, is the predominant species that readily complexes with metal ions in a 1:1 ratio.
For the equilibrium reaction of the metal with the Y4− form of EDTA, the formation...
For the equilibrium reaction of the metal with the Y4− form of EDTA, the formation...
01:26EDTA: Auxiliary Complexing Reagents
EDTA titrations are usually carried out in highly basic conditions, where the fully deprotonated form of EDTA, Y4−, actively complexes with the free metal ions in the solution. Several metal ions precipitate as hydrous oxide (hydroxides, oxides, or oxyhydroxides) under these conditions, lowering the concentration of free metal ions in the solution. For this reason, auxiliary complexing agents or ligands such as ammonia, tartrate, citrate, or triethanolamine are used in EDTA titrations to...