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Updated: Mar 26, 2026

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双二甲对控制分子间Diels-Alder反应的高外选择性具有独特的效

Zengjin Liu1, Xinglong Lin1, Na Yang2

  • 1Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education, Department of Medicinal Chemistry, West China School of Pharmacy, Sichuan University , Chengdu 610041, P. R. China.

Journal of the American Chemical Society
|January 23, 2016
PubMed
概括

双基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基 这种硬质控制为先进的有机合成提供了显著的潜力.

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Diels–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.
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Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.
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The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable,...
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The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
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In a Diels–Alder reaction, the diene is usually an electron-rich system and acts as a nucleophile, whereas the dienophile is electron-deficient and functions as an electrophile. Much like the diene, the nature of the dienophile significantly impacts the outcome of the reaction. 
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends...
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One of the critical aspects of the E1 reaction mechanism, as also observed in E2, is the regiochemistry, with multiple regioisomers obtained as products. In the example discussed, the presence of water as a weak base favors elimination over substitution to generate two alkenes. Given that alkenes’ stability increases with the number of alkyl groups across the double bond, typically, E1 reactions lead to the Zaitsev product, for this is more substituted and stable than the Hofmann product.
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