Table of Contents
Why is the Wittig reaction green?
The Wittig reaction has been modified to enhance green aspects of the reaction that is applicable to a broad array of aromatic aldehydes. An aromatic aldehyde is added to an ylide formed in situ by reacting benzyltriphenylphosphonium chloride with sodium hydroxide (Scheme 1).
What is green chemistry reaction?
Green chemistry is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances. Green chemistry applies across the life cycle of a chemical product, including its design, manufacture, use, and ultimate disposal.
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.
What happens in a Wittig reaction?
The Wittig Reaction allows the preparation of an alkene by the reaction of an aldehyde or ketone with the ylide generated from a phosphonium salt. If R is an electron withdrawing group, then the ylide is stabilized and is not as reactive as when R is alkyl.
Does Wittig react atom economy?
Atom economy (atom efficiency) describes the conversion efficiency of a chemical process in terms of all atoms involved (desired products produced). Note that atom economy can be poor even when chemical yield is near 100\%, e.g. the Cannizzaro reaction or the Wittig reaction.
Why do we need green chemistry?
Human health: Cleaner air: Less release of hazardous chemicals to air leading to less damage to lungs. Increased safety for workers in the chemical industry; less use of toxic materials; less personal protective equipment required; less potential for accidents (e.g., fires or explosions) …
Why is it important to consider green chemistry in organic synthesis?
green reactions allow avoiding problems with many environmental regulations and laws. Greener reactions are especially important in organic chemistry, where, due to a huge number of industrial processes with the use of hazardous chemicals and solvents, severe damage to the environment takes place.
Why is the Wittig reaction important?
The Wittig reaction provides a path from aldehydes and ketones to alkenes, and consequently is a valuable tool in organic synthesis. For example, the Wittig reaction will convert an α,β-unsaturated ketone to a conjugated alkene.
Is Wittig reaction stereoselective?
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.
Is known as Wittig reagent?
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. It is widely used in organic synthesis for the preparation of alkenes.
What is atom economy in green chemistry?
Green Chemistry Principle: Atom Economy. Atom economy means maximizing the incorporation of material from the starting materials or reagents into the final product. It is essentially pollution prevention at the molecular level.
What is the range of atom economy obtained for green synthesis?
72-82\%
Explanation: The atom economy obtained for green synthesis is in the range of 72-82\%. If the reaction is rearrangement reaction then the \% of atom economy is mostly 100\%.