Synthesis of cis-Norbornene-5,6-endo-dicaroboxylic anhydride Introduction: The main goal of this experiment is to perform a Diels-Alder reaction between 2,3-dimethyl-1,3-butadiene and maleic anhydride, identify the product and hydrolyze to form the dicarboxylic acid - Diels-Alder Reaction: Diels alder reactions are classified as pericyclic reaction, which is a reaction which involves a cyclic rearrangement of bonding electrons, which means that the bonds are broken and reformed instantaneously. When the experiment is complete a colorless platelike crystal will be formed and then they will be compared against the expected values.
Diels Alder Kinetics Sauer, J. A Review, Finguelli, F. Silyloxydienes in Organic Synthesis, Danishefsky, S. Tetrahedron48, Tetrahedron53, Tetrahedron57, The Diels-Alder reaction also known as the Diene Synthesis is the reaction of a 1,3-butadiene with an alkene to form a cyclohexene.
One of the first cycloadditions performed by Diels and Alder Nobel Prize was the reaction of cyclopentadiene with p-benzoquinone Diels, O.
Quinone cycloadditions have been frequently used in natural product syntheses, including the cyclopentadiene-benzoquinone adduct iteself in the synthesis of epi-Epoxydon.
Diels-Alder topics to be covered: Alder endo rule 5. Facial selectivity in diene and dienophile 6. Enantioselectivity - chiral auxiliaries and chiral catalysts 7. Inverse electron demand Diels-Alder reactions 8. Only dienes which can adopt the s-cis conformation undergo facile Diels-Alder reactions.
Any substitution pattern which favors the s-trans isomer slows down the cycloaddition. Especially unfavorable are cis-substituents on the diene, which usually prevent successful cycloadditions from being performed.
Most successful Diels-Alder reactions involve an electronic imbalance between diene and dienophile - usually the diene is electron rich the donor and the dienophile is electron poor the acceptor. Generally, 1-substituents have a larger reactivity effect than 2-substituents It is also possible to have Diels-Alder reactions with inverse electron demand, where the diene is electron deficient.
Because of the compact cyclic nature of the Diels-Alder transition state, the reaction is very sensitive to steric effects at all positions except the two central positions on the diene.
Alkyl groups on the dienophile are especially problematic because the electronic and steric effects are in the same direction. Stereospecificity The Diels-Alder reaction involves a stereospecific cis addition suprafacial to both the diene and dienophile. Existing stereochemical relationships in the dienophile cis or trans and the diene trans-trans or cis-trans are translated into stereochemical relationships in the product.
Stereoselectivity The Alder Endo Rule: The endo-selectivity is not usually very large, with values between 4: If the diene or dienophile does not have planar symmetry, then there may be substantial face-selectivity in Diels-Alder reactions resulting from combinations of steric and electronic effects.
Intermediate in prostaglandin synthesis: Regioselectivity The regioselectivity of the Diels-Alder reaction of unsymmetrical dienes with unsymmetrical dienophiles can be predicted by the ortho-para rule.
As with diene reactivity, 1-substituents generally have a larger directing effect than 2-substituents.The Diels Alder (DA) reaction remains in the realm of Organic Chemistry a major player in creating new-formed carbon-carbon bonds. This remarkable reaction is the protypical example of a . Explain why xylene is a good solvent for Diels-Alder reaction between anthracene and maleic anhydride.
Draw the structure (including stereochemistry) of the product you obtained in the experiment. Explain why the endo- product is formed in preference to the exo- product, although the exo- .
The Diels–Alder reaction is one of the most popular transformations for organic chemists to generate molecular complexity efficiently. Surprisingly, little is known about its industrial application for the synthesis of pharmacologically active ingredients, agrochemicals, and flavors and fragrances.
The Diels-Alder reaction is a special case of the more general class of cycloaddition reactions between (Pi) systems, the products of which are called cycloadducts. In the Diels-Alder reaction, an assembly of four conjugated atoms containing four electrons reacts with a double bond containing two electrons.
The post‐synthesis chemical modification of various porous carbon materials with unsaturated organic compounds is reported. By this method, amine, alcohol, carboxylate, and sulfonic acid functional groups can be easily incorporated into the materials. This week you’ll be creating a product via the Diels-Alder reaction.
The Diels-Alder is unlike other organic reactions in that it doesn’t involve any nucleophiles, leaving groups, or radicals, so there is no real mechanism to learn.