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  2. Addition reaction - Wikipedia

    en.wikipedia.org/wiki/Addition_reaction

    An addition reaction is the reverse of an elimination reaction, in which one molecule divides into two or more molecules. For instance, the hydration of an alkene to an alcohol is reversed by dehydration .

  3. Ketene cycloaddition - Wikipedia

    en.wikipedia.org/wiki/Ketene_cycloaddition

    The periselectivity of a particular reaction depends on the structure of both the ketene and the substrate. Although the reaction is predominantly used to form four-membered rings, a limited number of substrates undergo [3+2] or [4+2] reactions with ketenes. Examples of all three modes of cycloaddition are discussed in this section.

  4. Enone–alkene cycloadditions - Wikipedia

    en.wikipedia.org/wiki/Enone–alkene_cycloadditions

    The less hindered faces of the enone and alkene react. [9] Intramolecular enone–alkene cycloaddition may give either "bent" or "straight" products depending on the reaction regioselectivity. When the tether between the enone and alkene is two atoms long, bent products predominate due to the rapid formation of five-membered rings. [10]

  5. Syn and anti addition - Wikipedia

    en.wikipedia.org/wiki/Syn_and_anti_addition

    In organic chemistry, syn-and anti-addition are different ways in which substituent molecules can be added to an alkene (R 2 C=CR 2) or alkyne (RC≡CR).The concepts of syn and anti addition are used to characterize the different reactions of organic chemistry by reflecting the stereochemistry of the products in a reaction.

  6. Oxymercuration reaction - Wikipedia

    en.wikipedia.org/wiki/Oxymercuration_reaction

    The reaction follows Markovnikov's rule (the hydroxy group will always be added to the more substituted carbon). The oxymercuration part of the reaction involves anti addition of OH group but the demercuration part of the reaction involves free radical mechanism and is not stereospecific, i.e. H and OH may be syn or anti to each other. [2] [3] [4]

  7. Markovnikov's rule - Wikipedia

    en.wikipedia.org/wiki/Markovnikov's_rule

    Adding the hydrogen ion to one carbon atom in the alkene creates a positive charge on the other carbon, forming a carbocation intermediate. The more substituted the carbocation, the more stable it is, due to induction and hyperconjugation. The major product of the addition reaction will be the one formed from the more stable intermediate.

  8. Ene reaction - Wikipedia

    en.wikipedia.org/wiki/Ene_reaction

    In organic chemistry, the ene reaction (also known as the Alder-ene reaction by its discoverer Kurt Alder in 1943) is a chemical reaction between an alkene with an allylic hydrogen (the ene) and a compound containing a multiple bond (the enophile), in order to form a new σ-bond with migration of the ene double bond and 1,5 hydrogen shift.

  9. Reaction intermediate - Wikipedia

    en.wikipedia.org/wiki/Reaction_intermediate

    Carbocations are formed in two major alkene addition reactions. In an HX addition reaction, the pi bond of an alkene acts as a nucleophile and bonds with the proton of an HX molecule, where the X is a halogen atom. This forms a carbocation intermediate, and the X then bonds to the positive carbon that is available, as in the following two-step ...