Stereoselective total synthesis of (+)-licochalcone E
Zhiguo Liu1, Zengtao Wang, Goo Yoon
1College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 500-757, Korea.
Archives of Pharmacal Research
|September 13, 2011
Summary
Researchers achieved the first synthesis of (+)-licochalcone E, a complex natural product, using a 13-step route. This study details key asymmetric methylation for constructing the molecule
Area of Science:
- Organic Chemistry
- Natural Product Synthesis
- Asymmetric Synthesis
Background:
- Licochalcone E is a natural product with potential biological activities.
- Efficient synthetic routes are crucial for studying and utilizing natural products.
Purpose of the Study:
- To achieve the first total synthesis of (+)-licochalcone E.
- To develop a novel synthetic strategy for constructing the chiral center.
Main Methods:
- Palladium-catalyzed Negishi-Reformatsky coupling for C-C bond formation.
- Mixed anhydride method for amide synthesis.
- Chiral auxiliary-mediated asymmetric methylation for stereocenter installation.
Main Results:
- The total synthesis of (+)-licochalcone E was accomplished in 13 steps.
- An overall yield of 8% was achieved.
- A key asymmetric benzylic methyl group was successfully introduced.
Conclusions:
- The developed synthetic route provides access to (+)-licochalcone E.
- The methodology highlights the utility of chiral auxiliaries in asymmetric synthesis.
- This work enables further investigation into the biological properties of licochalcone E.
More Related Videos
Related Concept Videos
01:14Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
01:28Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.
02:57Sharpless Epoxidation
The conversion of allylic alcohols into epoxides using the chiral catalyst was discovered by K. Barry Sharpless and is known as Sharpless epoxidation. The use of a chiral catalyst enables the formation of one enantiomer of the product in excess. This chiral catalyst is mainly a chiral complex of titanium tetraisopropoxide and tartrate ester (specific stereoisomer). The stereoisomer used in the chiral catalyst dictates the formation of the enantiomer of the product. In other words, the use of...
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
01:29Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.