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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.
Phosphonium ion Structure of PH + 4, the parent phosphonium cation. In chemistry, the term phosphonium (more obscurely: phosphinium) describes polyatomic cations with the chemical formula PR + 4 (where R is a hydrogen or an alkyl, aryl, or halide group). These cations have tetrahedral structures. The salts are generally colorless or take the ...
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
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.
It is the bromide salt of a phosphonium cation. It is a white salt that is soluble in polar organic solvents. Synthesis and reactions ...
PPh 3 combines with alkyl halides to give phosphonium salts. This quaternization reaction is particularly fast for benzylic and allylic halides: PPh 3 + CH 3 I → [CH 3 PPh 3] + I −. These salts, which can often be isolated as crystalline solids, react with strong bases to form ylides, which are reagents in the Wittig reactions.
It undergoes a Wittig reaction. [1] ... This makes a phosphonium salt, which is converted to the final product by sodium carbonate in water. [1] Reactions