Concept explainers
(a)
Interpretation: The given reaction is to be classified as electrocyclic reaction, cycloaddition, or sigmatropic rearrangement. The stereochemistry whether the given reaction is conrotatory, disrotatory, suprafacial, or antarafacial is to be indicated.
Concept introduction: Electrocyclic reactions are pericyclic reactions which takes place by concerted mechanism. These reactions involve ring opening or ring closure in a conjugated polyene
(b)
Interpretation: The given reaction is to be classified as electrocyclic reaction, cycloaddition, or sigmatropic rearrangement. The stereochemistry whether the given reaction is conrotatory, disrotatory, suprafacial, or antarafacial is to be indicated.
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 in thermal conditions undergoes reaction in antrafacial fashion and polyene containing odd number of bonds undergo reaction in suprafacial fashion.
(c)
Interpretation: The given reaction is to be classified as electrocyclic reaction, cycloaddition, or sigmatropic rearrangement. The stereochemistry whether the given reaction is conrotatory, disrotatory, suprafacial, or antarafacial is to be indicated.
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.
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Chapter 27 Solutions
Package: Loose Leaf for Organic Chemistry with Biological Topics with Connect Access Card
- Problem 13.28 What reagent is needed to convert (CH3)2CHCH₂ COCI to each compound? a. b. C. d. но Ho ГОНarrow_forwardDraw the major products obtained from the reaction of one equivalent of HBr with the following compounds. For each reaction, indicate the kinetic product and the thermodynamic productarrow_forwardWhat product is formed when each compound undergoes thermal electrocyclic ring opening or ring closure? Label each process as conrotatory or disrotatory and clearly indicate the stereochemistry around tetrahedral stereogenic centers and double bonds.arrow_forward
- Ll.112.arrow_forwardIntramolecular Diels–Alder reactions are possible when a substrate contains both a 1,3-diene and a dienophile, as shown in the following general reaction.With this in mind, draw the product when each compound undergoes an intramolecular Diels–Alder reaction.arrow_forwardProvide the reagents. Но + enantiomer A 1. KOt-Bu, heat 2. mCPBA 3. MeMgBr 4. H2O B. 1. conc. H,SO4, heat 2. MCPBA 3. MeBr С. 1. РBгз 2. KOt-Bu 3. mCPBA 4. MeMgBr 5. H2O D. 1. Br2, hv 2. KOt-Bu 3. mCPBA 4. MeMgBr 5. H2O E. 1. Br2, hv 2. KOt-Bu 3. MCPBA 4. MeBr 5. H2O F. 1. Br2, FeBr3 2. KOt-Bu 3. mCPBA 4. MeMgBr 5. H2O G. 1. Br2, FeBr3 2. KOt-Bu 3. mCPBA 4. MeBr 5. H20arrow_forward
- Ll.113.arrow_forwardEpoxidation is a stereospecific reaction. Since the oxygen transfer occurs in a concerted step, the stereochemistry of the alkene is preserved in the epoxide. Thus, choosing a cis- vs. trans-alkene will provide different stereochemical outcomes. WS 2.22: Two diastereomers, cis-pent-2-ene vs. trans-pent-2-ene, are treated with mCPBA, followed by NaOCH3. Compare the stereochemistry of the products obtained from the two diastereomers.arrow_forwardConsider the following reaction scheme,arrow_forward
- EBK A SMALL SCALE APPROACH TO ORGANIC LChemistryISBN:9781305446021Author:LampmanPublisher:CENGAGE LEARNING - CONSIGNMENTOrganic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning