(a)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Cycloaddition reactions are pericyclic reactions that take place in two compounds containing pi bonds to form a cyclic compound. These reactions are concerted and stereospecific in nature. According to Woodward-Hoffmann rules, the polyene containing even number of bonds in thermal conditions undergoes reaction in antrafacial fashion and polyene containing odd number of bonds undergo reaction in suprafacial fashion. The total number of bonds present in the
(b)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Electrocyclic reactions involve ring opening or ring closure in a conjugated polyene. According to Woodward-Hoffmann rules, the polyene containing even number of bonds in photochemical conditions undergoes reaction in disrotatory fashion and polyene containing odd number of bonds undergo reaction in conrotatory fashion.
(c)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Cycloaddition reactions are pericyclic reactions that take place in two compounds containing pi bonds to form a cyclic compound. These reactions are concerted and stereospecific in nature. According to Woodward-Hoffmann rules, the polyene containing even number of bonds in photochemical conditions undergoes reaction in suprafacial fashion and polyene containing odd number of bonds undergo reaction in antrafacial fashion. The total number of bonds present in the alkenes is considered.
(d)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Sigmatropic rearrangements are pericyclic reactions which takes place by concerted mechanism. In these rearrangements migration of sigma bond takes place. According to Woodward-Hoffmann rules, the total number of electron pairs in sigma bond that is broken and the pi bonds that rearrange. The polyene containing even number of electron pairs and bonds in thermal conditions undergoes reaction in antrafacial fashion and polyene containing odd number of electron pairs and bonds undergo reaction in suprafacial fashion.
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Chapter 25 Solutions
Organic Chemistry (6th Edition)
- a. How many linear dienes have molecular formula C6H10? (Disregard cis–trans isomers.) b. How many of the linear dienes in part a are conjugated dienes? c. How many are isolated dienes? d. How many are cumulated dienes?arrow_forwardWhat is the major product of the following Diels-Alder cycloaddition? a. ₂CH3 X b. + CO₂CH3 CO₂CH3 CO₂CH3 d. CO₂CH3arrow_forwardDraw the products of the following reactions. If the products can exist as stereoisomers show what stereoisomers are formed. a. cis-2-pentene + Br2/CH2Cl2 b. trans-2-pentene + Br2/CH2Cl2 c. 1- butene + HCl d. methylcyclohexene + HBr e. trans-3-hexene + Br2/CH2Cl2 f. cis-3-hexene + Br2/CH2Cl2 g. 3,3-dimethyl-1-pentene + HBr h. cis-2-butene + HBr i. (Z)-2,3-dichloro-2-butene + H2, Pd/C j. (E)-2,3-dichloro-2-butene + H2, Pd/C k. (Z)-3,4-dimethyl-3-hexene + H2, Pd/C l. (E)-3,4-dimethyl-3-hexene + H2, Pd/Carrow_forward
- a. Show that [4+4] cycloaddition of two butadiene molecules to give cycloocta-1,5-diene is thermally forbidden but photochemically allowed b.Thermally allowed cycloaddition of the two butadiene molecules when there's a different. Show reaction and explain why it is thermally allowarrow_forwardDraw structural formulas for the diene and dienophile that combine in a Diels-Alder reaction to form the product shown CH3CH2O. Diene + Dienophile Co,CH3 •Consider E Z stereochemistry of alkenes. •Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. Separate multiple products using the sign from the drop-down menu. C. P. opy aste %3Darrow_forwardD. Provide a reasonable mechanism for the Diels-Alder reaction between two molecules of cyclopenta-1,3-diene. Br 1. Mg 2.CO₂ 3. H₂O* OHarrow_forward
- How many linear dienes have molecular formula C6H10? (Disregard cis–trans isomers.) A. How many of the linear dienes in part a are conjugated dienes? B. How many are isolated dienes? C. How many are cumulated dienes?arrow_forward2. Sketch the proper structure (including stereochemistry) for each compound. a. (4R)-3,4-diethyl-4-methylheptane b. (5S, 7R)-7-chloro-2,4,4,5,7-pentamethyldecane C. (65, 75)-3,7-dibromo-3-ethyl-6-methylnonanearrow_forwardh. 3-methyl-1-butene with Hg(OAC)2 and CH3OH, followed later by NaBH4 CH3 H2C=CH-CH-CH3 Major Product(s) of h. Stereochemistry of the product described in h. (Circle one) а. R b. S С. Е d. Z e. a mixture of E and Z f. erythro g. threo h. a racemic (50/50) mixture i. all 4 products (a set of erythro and a set of threo) j. no stereochemistryarrow_forward
- Draw the structure of the major organic product of the reaction below. CH3CH2 CH2CH3 Zn(Cu) C=C CH212 ether H H • Use the wedge/hash bond tools to indicate stereochemistry where it exists. • Show stereochemistry in a meso compound. • If the reaction produces a racemic mixture, just draw one stereoisomer. opy aste ChemDoodlearrow_forwardDetermine the double bond stereochemistry (E or Z) for the following molecules. F. H3C C A CH3 F. H B D Brarrow_forward6. Predict the major product for the following Diels-Alder reaction. 7. Which diene and dienophile would react to give the following Diels-Alder product? Сон 8. Which diene and dienophile would react to give the following Diels-Alder product? Illarrow_forward
