Diels–Alder reaction. In organic chemistry, the Diels–Alder reaction is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile (also spelled dieneophile), to form a substituted cyclohexene derivative.
Similarly, it is asked, how do we classify the Diels Alder reaction?
The Diels-Alder cycloaddition is classified as a [4+2] process because the diene has four pi-electrons that shift position in the reaction and the dienophile has two.
Also Know, what are the reactive intermediates involved in Diels Alder reactions? There are no reactive intermediates because it is a concerted mechanism, which means that in the transition state bonds are simultaneously made and broken.
People also ask, can a Diels Alder reaction occur with a triple bond?
Diels-Alder Reaction. The driving force of the reaction is the formation of new σ-bonds, which are energetically more stable than the π-bonds. In the case of an alkynyl dienophile, the initial adduct can still react as a dienophile if not too sterically hindered.
Why is the Diels Alder reaction stereospecific?
The Diels-Alder reaction is a concerted reaction, this means it occurs in only one step. Secondly, Diels-Alder reactions are stereospecific. This means that the substituents attached to the both the diene and the dienophile retain their stereochemistry throughout the reaction.
17 Related Question Answers Found
What are Diels Alder reactions used for?
Applications. The retro Diels–Alder reaction is used in the industrial production of cyclopentadiene. Cyclopentadiene is a precursor to various norbornenes, which are common monomers. The Diels–Alder reaction is also employed in the production of vitamin B6.
What happens in a Diels Alder reaction?
Description: The Diels Alder reaction converts a diene and an alkene (usually electron-poor, called a “dienophile”) into a six-membered ring containing an alkene (cyclohexene). Notes: X here is usually an electron withdrawing group such as a ketone, ester, or CN. That is to say that the reaction is stereospecific.
What makes a Dienophile more reactive?
Dienophile reactivity is increased by: (A) electron-withdrawing substituents, (B) a weak π-bond, and (C) release of ring strain.
When was the Diels Alder reaction discovered?
Diels-Alder Cycloaddition The Diels-Alder (DA) reaction is one of the most common and important reaction used in organic chemistry to synthesize cyclic compounds. It was discovered by Otto Diels and Kurt Alder who received the Nobel Prize for their discovery in 1950.
Who discovered the Diels Alder reaction?
Otto Diels
What is a Dienophile definition?
dienophile (plural dienophiles) (organic chemistry) A compound that readily reacts with a diene; especially an alkene in the Diels-Alder reaction.
Why does anthracene undergo Diels Alder reaction?
Anthracene undergoes a Diels-Alder reaction with maleic anhydride to give a cycloadduct with the formula C18H12O3. The Diels-Alder reaction is the conjugate addition of an alkene to a diene. The alkene that adds to the diene is called dienophile.
How many new bonds and of what type are created in a Diels Alder reaction?
The pattern of the Diels-Alder calls for breaking three pi bonds and forming two single bonds and a pi bond, resulting in a six-membered ring. Any bonds to the substituents on the diene/dienophile do NOT break.
Which diene will react the fastest in the Diels Alder reaction?
In general, Diels-Alder reactions proceed fastest with electron-donating groups on the diene (eg. alkyl groups) and electron-withdrawing groups on the dienophile.
What is the endo Rule?
The exo product is more stable, but the activation energy for endo is lower, so the less stable endo product is formed faster. At lower temperatures, kinetic control prevails and the less stable endo isomer is the main product.
Why is Endo favored?
The endo product is kinetically favored, which means that under conditions of low temperature and limited time, it will be the major product that is formed. This is because the transition state of the formation of the endo product is lower in energy due to overlap of secondary orbitals.
Is the Dienophile the Electrophile?
The dienophile is electron-poor (the electrophile). When your dienophile has substituents on it that take away electron density (pi acceptors like carbonyl groups) it is more electron poor – and a better electrophile.
Why is Diels Alder syn addition?
This hydroboration-oxidation reaction is a syn addition because this reaction delivers an H and OH to the same face of the alkene. This Diels-Alder reaction is a syn cycloaddition reaction because the two new carbon-carbon sigma bonds are formed on the same face of the diene or dienophile.
What is the stereochemistry requirement in Diels Alder reactions?
Summary: Stereochemistry of the Diels-Alder Reaction The “outside” groups on the diene end up on the same face of the new six-membered ring, as do the “inside” groups. When both the diene and dienophile are substituted, diastereomers may form, which we call “exo” and “endo”.
Is Diels Alder exothermic?
A Diels-Alder involves the reaction of a diene with a dienophile to form a cyclohexene derivative. We can use bond dissociation energies ( D ) to calculate an approximate value of ΔH for this reaction. This is only a rough value, but it shows that the formation of four new C-C bonds makes the reaction quite exothermic.
Which of the following Conjugated Dienes would not react with a dienophile in a Diels Alder reaction?
The given diene has s-trans conformation. S-trans conformation cannot undergo a Diels-Alder reaction, because in an s-trans conformation the number 1 and number 4 carbons are too far apart to react with the dienophile. Thus, the given diene cannot react with dienophile in a Diels-Alder reaction.
How many chiral centers were created in your Diels Alder reaction?
four chiral centers