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Wittig reagents are usually described as a combination of two resonance structures: Ph 3 P + CR 2 − ↔ Ph 3 P=CR 2 The former is called the ylide form and the latter is called the phosphorane form, which is the more familiar representation.
1 Preparation and use. 2 Structure. 3 Uses. 4 Related reagents. 5 References. ... It is the parent member of the phosphorus ylides, popularly known as Wittig reagents ...
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 ...
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.
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.
These carbene reagents add to alkenes to give substituted cyclopropanes and cyclopropenes. [4] To deprotonation of phosphonium salts, generating Wittig reagents. NaHMDS deprotonates compounds containing weakly acidic O–H, S–H, and N–H bonds. These include cyanohydrins and thiols. [5]
The Aza-Wittig reaction or is a chemical reaction of a carbonyl group with an aza-ylide, also known as an iminophosphorane (R 3 P=NR'). Aza-Wittig reactions are most commonly used to convert aldehydes and ketones to the corresponding imines . [ 1 ]
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