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Chapitre 8

Réactions des alcènes

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Régiosélectivité des additions électrophiles - effet Kharasch

In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. ...

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Réaction en chaîne de radicaux libres et polymérisation des alcènes

The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a ...

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Halogénation des alcènes

Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence ...

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Formation d'halohydrine à partir d'alcènes

An alkene, such as propene, reacts with bromine in the presence of water to yield a halohydrin. Halohydrins contain a halogen and a hydroxyl group ...

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Hydratation des alcènes catalysée par l'acide

Alkenes react with water in the presence of an acid to form an alcohol. In the absence of acid, hydration of alkenes does not occur at a significant rate, ...

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Régiosélectivité et stéréochimie de l'hydratation catalysée par l'acide

The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can ...

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Oxymercuration-réduction des alcènes

Oxymercuration–reduction of alkenes is one of the major reactions converting alkenes to alcohols. It involves the hydration of alkenes with mercuric ...

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Hydroboration-oxydation des alcènes

In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary ...

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Régiosélectivité et stéréochimie de l'hydroboration

A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction. Hydroboration proceeds in a concerted ...

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Oxydation des alcènes : dihydroxylation SYN avec le tétroxyde d'osmium

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 ...

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Oxydation des alcènes : dihydroxylation SYN avec le permanganate de potassium

Alkenes can be dihydroxylated using potassium permanganate. The method encompasses the reaction of an alkene with a cold, dilute solution of ...

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Oxydation des alcènes : anti-dihydroxylation avec des acides peroxy

Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti ...

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Clivage oxydatif des alcènes : ozonolyse

In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up. ...

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Réduction des alcènes : hydrogénation catalytique

Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a ...

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Réduction des alcènes : hydrogénation catalytique asymétrique

Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of ...