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  2. Mevalonate pathway - Wikipedia

    en.wikipedia.org/wiki/Mevalonate_pathway

    The mevalonate pathway of eukaryotes, archaea, and eubacteria all begin the same way. The sole carbon feed stock of the pathway is acetyl-CoA. The first step condenses two acetyl-CoA molecules to yield acetoacetyl-CoA. This is followed by a second condensation to form HMG-CoA (3-hydroxy-3- methyl-glutaryl-CoA).

  3. Substitution reaction - Wikipedia

    en.wikipedia.org/wiki/Substitution_reaction

    The two reactions are named according tho their rate law, with S N 1 having a first-order rate law, and S N 2 having a second-order. [2] S N 1 reaction mechanism occurring through two steps. The S N 1 mechanism has two steps. In the first step, the leaving group departs, forming a carbocation (C +). In the second step, the nucleophilic reagent ...

  4. Ring expansion and contraction - Wikipedia

    en.wikipedia.org/wiki/Ring_expansion_and_contraction

    Working with two smaller rings can allow for elaboration of two parts of the molecule separately before working with the expanded ring. The Dowd-Beckwith ring expansion reaction is also capable of adding several carbons to a ring at a time, and is a useful tool for making large rings. [ 11 ]

  5. Trifluoromethyl cation - Wikipedia

    en.wikipedia.org/wiki/Trifluoromethyl_cation

    It is a carbocation due to its positively charged carbon atom. It is part of the family of carbenium ions , with three fluorine atoms as substituents in place of its hydrogen atoms. [ 1 ]

  6. Carbocation - Wikipedia

    en.wikipedia.org/wiki/Carbocation

    In the present-day definition given by the IUPAC, a carbocation is any even-electron cation with significant partial positive charge on a carbon atom. They are further classified in two main categories according to the coordination number of the charged carbon: three in the carbenium ions and five in the carbonium ions.

  7. Carbene - Wikipedia

    en.wikipedia.org/wiki/Carbene

    Methylene is the simplest carbene.. In organic chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons.The general formula is R−:C−R' or R=C: where the R represents substituents or hydrogen atoms.

  8. Carbonium ion - Wikipedia

    en.wikipedia.org/wiki/Carbonium_ion

    The 2-norbornyl cation is one of the best characterized carbonium ion. It is the prototype for non-classical ions. As indicated first by low-temperature NMR spectroscopy and confirmed by X-ray crystallography, [1] it has a symmetric structure with an RCH 2 + group bonded to an alkene group, stabilized by a bicyclic structure.

  9. Reaction intermediate - Wikipedia

    en.wikipedia.org/wiki/Reaction_intermediate

    E1 and E2 are two different mechanisms for elimination reactions, and E1 involves a carbocation intermediate. In E1, a leaving group detaches from a carbon to form a carbocation reaction intermediate. Then, a solvent removes a proton, but the electrons used to form the proton bond form a pi bond, as shown in the pictured reaction on the right. [4]