Diels Alder Reaction Virtual Lab Simulation

General Aim

Synthesis of six member cyclic organic compounds.

Method

Electrocyclic reaction where 4 π-electrons from the conjugated diene (anthracene) and 2 π-electrons from the dienophile (maleic anhydride) are involved in the reaction in the presence xylene as a solvent at temperature of 350 ⁰C. The driving force is the formation of new σ-bonds as they are energetically more stable than the π-bonds.

Theoretical Background/Context

The Diels-Alder reaction is one of the most important reactions of organic chemistry since they are used in synthesizing six-membered ringed cyclic organic compounds.

It is also considered as a [4+2]-cycloaddition reaction because it involves the an addition reaction between a conjugated diene molecule and a substituted alkene (dienophile) in order to produce a substituted cyclohexene system. 

Specifically, 4 π-electrons from the conjugated diene and 2 π-electrons from the dienophile are involved in the reaction. Therefore, it is counted as an electrocyclic reaction whose driving force is the formation of new σ-bonds as they are energetically more stable than the π-bonds.

Furthermore, Diels-Alder reaction is known as a non-polar reactions since no charged intermediates are formed during the reaction. In addition, no unpaired electrons are involved in the addition reaction. It is considered as a concerted reaction since several bonds are formed and broken simultaneously during the transition state.

Principle of Work

An example of Diels Alder reaction is the cycloaddition of anthracene (conjugated diene) and maleic anhydride (dienophile) to form 9,10-dihydroanthracene-9,10-endo-a3-succinic anhydride. Xylene is used as the reaction solvent due to its high-boiling that could accommodate the high temperature needed for running the chemical reaction. 
Maleic anhydride is known as a highly reactive dienophile owing to the presence of two electron withdrawing carbonyl substituents within its chemical structure. On the other hand, anthracene is not a highly reactive diene because of both its steric hindrance in addition to its high stability due to aromaticity.