Radical Elimination
Radical Elimination - Related Videos
00:51
Radical Formation: Elimination
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2023
Another method of radical formation is the elimination process. It is the opposite of the addition route and is driven by the instability of the radical. For example, as depicted in Figure 1, dibenzoyl peroxide yields a pair of unstable radicals upon homolysis. Given its instability, this radical spontaneously undergoes elimination via a C–C bond cleavage to form a relatively more stable phenyl radical. The mechanism involves cleavage of the bond between the α and β positions with respect to...
14:22
Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
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Cited by 9 •
2013
Radical-based biomimetic chemistry has been applied to building-up libraries necessary for biomarker development.
10:29
Photochemical Initiation Of Radical Polymerization Reactions
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2023
Source: David C. Powers, Tamara M. Powers, Texas A&M In this video, we will carry out the photochemically initiated polymerization of styrene to generate polystyrene, which is an important commodity plastic. We will learn the fundamentals of photochemistry and use simple photochemistry to initiate radical polymerization reactions. Specifically, in this module we will examine the photochemistry of benzoyl peroxide and its role as a photo-initiator of styrene polymerization reactions. In the...
01:02
Radical Reactivity: Electrophilic Radicals
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2023
Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For example, the malonate radical, in which the radical center is flanked by two electron‐withdrawing groups, reacts readily with butyl vinyl ether, which consists of an electron‐donating oxygen substituent. The reaction between electrophilic malonate radical and nucleophilic vinyl ether is favored because the radical has a low‐energy SOMO, which interacts...
01:16
Radical Reactivity: Nucleophilic Radicals
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2023
Radicals adjacent to electron-donating groups are called nucleophilic radicals. These radicals readily react with electrophilic alkenes. The SOMO–LUMO interactions are the driving force for the reaction, where the high-energy SOMO of the electron-rich, nucleophilic radicals interacts with the low-energy LUMO of the electron-deficient, electrophilic alkenes. Such SOMO–LUMO interactions are the basis of reactive radical traps, affecting the selectivity in radical reactions. For instance, consider...
FAQs
Single-electron steps make radical intermediates central to the reaction pathway rather than relying on the polar, ionic intermediates associated with conventional elimination. This distinction affects how bonds break and how the new π bond forms. Examining the radical pathway helps chemists anticipate reactivity that would not be predicted from polar elimination rules alone.
β-Scission provides the key bond-cleavage event in which a carbon-centered radical expels a substituent or atom while generating a π bond. The process links radical formation directly to alkene construction. Recognizing this relationship allows researchers to connect the structure of a radical intermediate with the multiple-bond product expected from the transformation.
Heat, light, and radical reagents can initiate the conditions required for radical reactivity. Because these inputs differ from the conditions associated with ionic elimination, they provide alternative ways to access alkene-forming pathways. Selecting among them is therefore part of designing a transformation that favors radical behavior over competing reaction routes.
The two processes differ in both the type of electron movement and the intermediates involved. Radical elimination proceeds through single-electron chemistry and radical species, whereas polar elimination follows an ionic logic. This mechanistic contrast matters because the same starting structure may show different competing pathways depending on whether radical or polar conditions are used.
Researchers should consider which radical intermediates can form, whether β-scission can produce the desired π bond, and which competing pathways may operate under the chosen conditions. This analysis supports prediction before experimentation and helps guide the design of selective transformations. The goal is to favor the intended alkene-forming route within a broader reaction network.
The reaction offers a route to construct alkenes under conditions distinct from ionic elimination, expanding the strategies available for synthetic chemistry. Alkene formation can serve as a useful structural change during the assembly of complex organic molecules. Its value lies not only in the product, but also in the mechanistic flexibility provided by radical intermediates and initiation methods.