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  2. Wagner–Meerwein rearrangement - Wikipedia

    en.wikipedia.org/wiki/Wagner–Meerwein...

    A Wagner–Meerwein rearrangement is a class of carbocation 1,2-rearrangement reactions in which a hydrogen, alkyl or aryl group migrates from one carbon to a neighboring carbon. [ 1 ] [ 2 ] They can be described as cationic [1,2]- sigmatropic rearrangements, proceeding suprafacially and with stereochemical retention.

  3. Ring expansion and contraction - Wikipedia

    en.wikipedia.org/wiki/Ring_expansion_and_contraction

    The cationic rearrangement contraction proceeds through the loss of a leaving group and the migration of an endocyclic bond to the carbocation. Pinacol type rearrangements are often used for this type of contraction. [20] Like the expansion reaction this proceeds with an electron donating group aiding in the migration.

  4. Friedel–Crafts reaction - Wikipedia

    en.wikipedia.org/wiki/Friedel–Crafts_reaction

    Also, there are no carbocation rearrangements, as the acylium ion is stabilized by a resonance structure in which the positive charge is on the oxygen. The viability of the Friedel–Crafts acylation depends on the stability of the acyl chloride reagent. Formyl chloride, for example, is too unstable to be isolated.

  5. Farnesyl-diphosphate farnesyltransferase - Wikipedia

    en.wikipedia.org/wiki/Farnesyl-diphosphate_farne...

    From PSPP, squalene is formed by a series of carbocation rearrangements. [12] [13] The process begins with ionization of pyrophosphate, giving a cyclopropylcarbinyl cation. The cation rearranges by a 1,2-migration of a cyclopropane C–C bond to the carbocation, forming the bond shown in blue to give a cyclobutyl carbocation. Subsequently, a ...

  6. Rearrangement reaction - Wikipedia

    en.wikipedia.org/wiki/Rearrangement_reaction

    In organic chemistry, a rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. [1] Often a substituent moves from one atom to another atom in the same molecule, hence these reactions are usually intramolecular.

  7. Substitution reaction - Wikipedia

    en.wikipedia.org/wiki/Substitution_reaction

    Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to ...

  8. Markovnikov's rule - Wikipedia

    en.wikipedia.org/wiki/Markovnikov's_rule

    Anti-Markovnikov rearrangement. This product distribution can be rationalized by assuming that loss of the hydroxy group in 1 gives the tertiary carbocation A, which rearranges to the seemingly less stable secondary carbocation B. Chlorine can approach this center from two faces leading to the observed mixture of isomers.

  9. Carbocation - Wikipedia

    en.wikipedia.org/wiki/Carbocation

    A carbocation is an ion with a positively charged carbon atom. ... the E1 reaction, and in rearrangement reactions such as the Whitmore 1,2 shift. The chemical ...