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Wittig reagents are usually prepared from a phosphonium salt, which is in turn prepared by the quaternization of triphenylphosphine with an alkyl halide. Wittig reagents are usually derived from a primary alkyl halide. Quaternization of triphenylphosphine with secondary halides is typically inefficient.
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 ...
It is the parent member of the phosphorus ylides, popularly known as Wittig reagents. It is a highly polar, highly basic species. It is a highly polar, highly basic species. Preparation and use
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.
This reagent reacts with a ketone or aldehyde in a Wittig reaction to give an enol ether, which can be converted to the aldehyde by acid-induced hydrolysis. The initial report of the reaction demonstrated its use on the steroid tigogenone. It was later used in the Wender Taxol total synthesis and the Stork quinine total synthesis.
Reaction of Weinreb–Nahm amides with Wittig reagents. Additionally, a one-pot magnesium–halogen exchange with subsequent arylation has been developed, showcasing the stability of the Weinreb–Nahm amide and providing an operationally simple method for the synthesis of aryl ketones. [11] One-pot arylation reaction
An example of the aza-Wittig-reaction being utilized in organic synthesis is the synthesis of (–)-benzomalvin A. Two intramolecular aza-Wittig-reactions were used to construct the seven-membered ring and the six-membered ring in the molecule's skeleton. [1] Synthesis of (−)-Benzomalvin A via multiple aza-Wittig-reactions
Georg Wittig (German: [ˈɡeː.ɔʁk ˈvɪ.tɪç] ⓘ; 16 June 1897 – 26 August 1987) was a German chemist who reported a method for synthesis of alkenes from aldehydes and ketones using compounds called phosphonium ylides in the Wittig reaction. He shared the Nobel Prize in Chemistry with Herbert C. Brown in 1979.