What is Wittig reaction with example?

Wittig reaction is an organic chemical reaction wherein an aldehyde or a ketone is reacted with a Wittig Reagent (a triphenyl phosphonium ylide) to yield an alkene along with triphenylphosphine oxide. This Reaction is named after its discoverer, the German chemist Georg Wittig.

What does the Wittig reaction produce?

The Wittig reaction converts carbonyl compounds into alkenes. In such reactions, phosphorus ylides are produced from a phosphonium salt and a base. This ylide reacts with a carbonyl compound to give an alkene.

What is Wittig Horner reaction?

Horner-Wadsworth-Emmons Reaction. The reaction of aldehydes or ketones with stabilized phosphorus ylides (phosphonate carbanions) leads to olefins with excellent E-selectivity.

Is Wittig a Stereoselectivity reaction?

The Z-stereoselective Wittig reaction consists of a stereoselective first step forming the syn oxaphosphetane. This is then followed by a stereospecific elimination of this intermediate to form the Z alkene.

What is the modified Wittig reaction?

The Schlosser Modification of the Wittig Reaction allows the selective formation of E-alkenes through the use of excess lithium salts during the addition step of the ylide and subsequent deprotonation/protonation steps.

What is Wittig reagent and how it is prepared?

Wittig reagents are usually prepared from a phosphonium salt, which is in turn prepared by the reaction of triphenylphosphine with an alkyl halide via an SN2 reaction. The alkylphosphonium salt is deprotonated with a strong base such as n-butyllithium: [Ph3P+CH2R]X− + C4H9Li → Ph3P=CHR + LiX + C4H. 10.

How is the Wittig reaction modified?

What is the difference between Wittig reaction and Horner Wadsworth Emmons reaction?

Wittig reaction and Wittig Horner reaction are important synthesis reactions that produce alkenes from aldehydes or ketones. The key difference between Wittig and Wittig Horner reaction is that Wittig reaction uses phosphonium ylides, whereas Wittig Horner reaction uses phosphonate-stabilized carbanions.

What type of reaction is Wittig?

The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide (often called a Wittig reagent) to give an alkene and triphenylphosphine oxide.

Is Wittig a reaction Sn2?

The Three Steps of the Wittig Reaction. The first step of the sequence involves an Sn2 reaction in which the phosphorous displaces the bromine from the methyl bromide.

How was the Wittig reaction discovered?

In investigating reactions involving carbanions, negatively charged organic species, Wittig discovered a class of organic phosphorus compounds called ylides that mediate a particular type of reaction that became known as the Wittig reaction.