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  2. Wittig reaction - Wikipedia

    en.wikipedia.org/wiki/Wittig_reaction

    The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagent. Wittig reactions are most commonly used to convert aldehydes and ketones to alkenes. [1] [2] [3] Most often, the Wittig reaction is used to introduce a methylene group using ...

  3. Wittig reagents - Wikipedia

    en.wikipedia.org/wiki/Wittig_reagents

    For stabilized Wittig reagents bearing conjugated electron-withdrawing groups, even relatively weak bases like aqueous sodium hydroxide or potassium carbonate can be employed. [Ph 3 PCH 3] + Br −, typical phosphonium salt. The identification of a suitable base is often an important step when optimizing a Wittig reaction.

  4. 1,2-Wittig rearrangement - Wikipedia

    en.wikipedia.org/wiki/1,2-Wittig_rearrangement

    A 1,2-Wittig rearrangement is a categorization of chemical reactions in organic chemistry, and consists of a 1,2-rearrangement of an ether with an alkyllithium compound. [1] The reaction is named for Nobel Prize winning chemist Georg Wittig. [2] [3] The intermediate is an alkoxy lithium salt, and the final product an alcohol.

  5. Schiff base - Wikipedia

    en.wikipedia.org/wiki/Schiff_base

    A mixture of 4,4'-oxydianiline 1 (1.00 g, 5.00 mmol) and o-vanillin 2 (1.52 g, 10.0 mmol) in methanol (40.0 ml) is stirred at room temperature for one hour to give an orange precipitate and after filtration and washing with methanol to give the pure Schiff base 3 (2.27 g, 97%) Schiff bases can also be synthesized via the Aza-Wittig reaction.

  6. 2,3-Wittig rearrangement - Wikipedia

    en.wikipedia.org/wiki/2,3-Wittig_rearrangement

    The [2,3]-Wittig rearrangement is the transformation of an allylic ether into a homoallylic alcohol via a concerted, pericyclic process.Because the reaction is concerted, it exhibits a high degree of stereocontrol, and can be employed early in a synthetic route to establish stereochemistry.

  7. Ylide - Wikipedia

    en.wikipedia.org/wiki/Ylide

    An ylide (/ ˈ ɪ l aɪ d /) [1] or ylid (/ ˈ ɪ l ɪ d /) is a neutral dipolar molecule containing a formally negatively charged atom (usually a carbanion) directly attached to a heteroatom with a formal positive charge (usually nitrogen, phosphorus or sulfur), and in which both atoms have full octets of electrons.

  8. Methylenation - Wikipedia

    en.wikipedia.org/wiki/Methylenation

    A common method for methylenation involves the Wittig reaction using methylenetriphenylphosphorane with an aldehyde (Ph = phenyl, C 6 H 5): [4] + = = + A related reaction can be accomplished with Tebbe's reagent, which is sufficiently versatile to allow methylenation of esters: [5]

  9. Horner–Wadsworth–Emmons reaction - Wikipedia

    en.wikipedia.org/wiki/Horner–Wadsworth–Emmons...

    The Horner–Wadsworth–Emmons (HWE) reaction is a chemical reaction used in organic chemistry of stabilized phosphonate carbanions with aldehydes (or ketones) to produce predominantly E-alkenes. [1] The Horner–Wadsworth–Emmons reaction. In 1958, Leopold Horner published a modified Wittig reaction using phosphonate-stabilized carbanions.