Concept explainers
Interpretation:
The transition states of exo and endo Diels Ander reactions of maleic anhydride with cyclopentadiene are to be drawn. Also, the transition state that leads to only one enantiomer need to be shown in each.
Concept introduction:
A Diels Ander reaction is one between a conjugate diene and a reactant containing a double bond (dienophile) to form a product. The product is called adduct.
Diels Ander reactions are highly stereospecific. The configuration of the dienophile is retained in the product and the reaction is a syn addition reaction.
The dienes react with dienophiles in cis forms rather than trans forms.
Endo and exo refer to the orientation of the dienophile and its electron-withdrawing group when it reacts with a diene in a Diels Ander reaction.
Endo is favored in the transition state of a Diels Ander reaction because it has a lower energy.
Want to see the full answer?
Check out a sample textbook solutionChapter 13 Solutions
Organic Chemistry
- -Ocimene is a pleasant-smelling hydrocarbon found in the leaves of certain herbs. It has the molecular formula C10H16 and a UV absorption maximum at 232 nm. On hydrogenation with a palladium catalyst, 2,6-dimethyloctane is obtained. Ozonolysis of -ocimene, followed by treatment with zinc and acetic acid, produces the following four fragments: (a) How many double bonds does -ocimene have? (b) Is -ocimene conjugated or nonconjugated? (c) Propose a structure for -ocimene. (d) Write the reactions, showing starting material and products.arrow_forwardHydrocarbon 10 and ester 12 react upon heating to give a cycloaddition product D. (i) Suggest a structure for product D and provide a curved arrow mechanism that accounts for its formation. (ii) Draw the molecular orbitals corresponding to the HOMO of 10 and the LUMO of 12 and show that these are of suitable symmetry for a concerted cycloaddition to take place. (iii) Use frontier molecular orbital theory to account for the observation that the formation of D is faster in the presence of AlCl3. please answer all thank youarrow_forward1,4-Benzoquinone is a good Diels–Alder dienophile. Predict the products of its reaction with(a) buta-1,3-dienearrow_forward
- The following triene undergoes an intramolecular Diels-Alder reaction to give a bicyclic product. Propose a structural formula for the product. Account for the observation that the Diels-Alder reaction given in this problem takes place under milder conditions (at lower temperature) than the analogous Diels-Alder reaction 0"C Diels-Alder adductarrow_forwardStyrene (vinylbenzene) undergoes electrophilic aromatic substitution much faster thanbenzene, and the products are found to be primarily ortho- and para-substituted styrenes.Use resonance forms of the intermediates to explain these results.arrow_forward(a) Complete the following sequence of reactions (i.e., give the structure for compounds A and B), giving structural details of all key intermediates. heat & A COOCH3 H₁₂ Ni (b) Provide the bond line structures for the pair of compounds used for the Diels-Alder synthesis of the compound shown below. O B COOCH3 (c) Draw the two major products obtained when (3E,5Z)-2,2,3,6,7-pentamethylocta-3,5-diene reacts with HBr at low and high temperatures. Label the products as the kinetic or thermodynamic product AND, if applicable, use dashes and wedges to show the correct stereochemistry in the obtained products.arrow_forward
- The highly reactive triple bond of benzyne is a powerful dienophile. Predict the productof the Diels–Alder reaction of benzyne (from chlorobenzene and NaOH, heated) withcyclopentadiene.arrow_forward14. Please write the major product for each following Diels-Alder reaction. Explain why they are formed by using Frontier Molecular Orbital theory. (a) 1-(diethylamino)-1,3-butadiene + acrylate (b) 2-ethoxy-1,3-butadiene + acrylate Moreover, draw Molecular Orbitals of 1-(diethylamino)-1,3-butadiene, 2-ethoxy-1,3-butadiene & acrylate. In addition, mark energy levels and predict the products by using FMO theory.arrow_forward(9) SN2 Reactions - Predicting Reaction Products. Complete the reactions shown below by drawing the structure of the substitution product. It is not necessary to balance the equations. Draw the proper product stereochemistry, if relevant (inversion of configuration for SN2). acetone NaCI Br DMF NaOH (b) acetone (c) NaCNarrow_forward
- Using the Woodward–Hoffmann rules, predict the stereochemistry of belowreaction. a thermal [5,5] sigmatropic rearrangementarrow_forwardGive reasons : (i) 2, 4-Dinitro chlorobenzene is much more reactive than chlorobenzene towards hydrolysis reaction with NaOH. (ii) Grignard reagent should be prepared under anhydrous conditions. (iii) The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride. (vi) Neopentyl bromide undergoes nucleophilic substitution reactions very slowly (v) Vinyl chloride is unreactive in nucleophilic substitution reaction. (vi) An optically inactive product is obtained after the hydrolysis of optically active 2- bromobutane.arrow_forwardA key step in the synthesis of naproxen, an NSAID more commonly known by its brand name, Aleve (Section 3.9), is a coupling reaction of 2-bromo-6-methoxynaphthalene to form 2-methoxy-6-vinylnaphthalene. Show three different coupling reactions, and the required reagents, that could be used tocarry out this step.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning