During studies directed toward the synthesis of atropurpuran, a diterpene with interesting molecular architecture, the investigators used high temperature to convert an acyclic tetraene into a tricyclic compound, shown below. (Org. Lett. 2010, 12, 1152-1155). This transformation is believed to occur via two successive pericyclic processes (an electrocyclic ring-closing reaction, followed by a Diels- Alder cycloaddition). Draw the mechanism as described. R₂N. NTS 135°C R₂N NTS

During studies directed toward the synthesis of atropurpuran, a diterpene with interesting molecular architecture, the investigators used high temperature to convert an acyclic tetraene into a tricyclic compound, shown below. (Org. Lett. 2010, 12, 1152-1155). This transformation is believed to occur via two successive pericyclic processes (an electrocyclic ring-closing reaction, followed by a Diels- Alder cycloaddition). Draw the mechanism as described. R₂N. NTS 135°C R₂N NTS

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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Following is an example of a type of reaction known as a Diels-Alder reaction 1,3-Pentadiene Ethylene 3-Methylcyclohexene (a racemic mixture) The Diels-Alder reaction between a diene and an alkene is quite remarkable in that it is one of the few ways that chemists have to form two new carbon-carbon bonds in a single reaction. Given what you know about the relative strengths of carbon-carbon sigma and pi bonds, would you predict the Diels-Alder reaction to be exothermic or endothermic? Explain your reasoning.
Draw structural formulas for the diene and dienophile that combine in a Diels-Alder reaction to form the product shown. CN Diene + Dienophile CH₂O • Consider E/Z stereochemistry of alkenes. CN
A very large number of Diels-Alder reactions are recorded in the chemical literature, many of which involve relatively complicated dienes, dienophiles, or both. Predict the constitution of the Diels-Alder adduct that is expected to form from the combination of diene and dienophile below. Draw the structure of the predicted product, including relevant stereochemistry when applicable. If applicable, use the Bicyclic Stamp tool and guide points to draw each structure. Click and drag to start drawing a structure.
Predict the product(s) of the following Diels-Alder reaction. Include stereochemistry if appropriate.
The name of the product of this Diels Alder react, including stereochemistry, is: CH₂ CH₂ + CI CI heat cis 5,6-dichloro-1,3-cyclohexadiene trans- 5,6-dichloro-1,3-cyclohexadiene trans 4,5-dichlorocyclohexene O cis 4,5-dichlorocyclohexene
Indicate the reagents (diene and phyllodiene) necessary to obtain the following compound by a Dirls-Alder reaction. CH3 CH3 COOH COOH
The following compound undergoes an intramolecular Diels-Alder reaction to give a tricyclic product. Propose a structural formula for the product. heat An intramolecular Diels-Alder adduct
Heating the following molecule in ethanol gave a major product with molecular formula C,H12 , which when treated with O3 followed by Me2S produced the diketone shown. Br CH3CH,OH 1. O3 C,H12 heat 2. Me,S (i) Deduce the structure of the product with molecular formula C,H12 from the information provided. Write an arrow formalism reaction mechanism to show how the compound with molecular formula C,H12 is formed. (ii) How would you perform the following transformation to obtain the final product as the MAJOR product. More than one step is needed. Show all the steps in your synthesis. Reaction mechanisms are not required. Br more than one step less than four steps OHC CHO
1)Chemistry students are taking an experimental course in organic chemistry at a public university. During an experiment involving conjugated dienes, some doubts arose when discussing the results obtained so far: (a) A student obtained two products from the reaction of 1,3-cyclohexadiene with Br2. His lab partner was surprised to get only one product from the reaction of 1,3 - cyclohexadiene with HBr. Explain these distinct results. (b) One student, seeing the discussion of colleagues, commented that she obtained two distinct products when reacting 1,3,5-hexatriene with HBr, with different yields just by changing the reaction temperature. Explain the results she obtained using reaction mechanism and based on kinetic and thermodynamic control involving conjugated dienes.
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