CHEM 2425. Chapter 18. Ethers and Epoxides, Exams of Organic Chemistry

Download CHEM 2425. Chapter 18. Ethers and Epoxides and more Exams Organic Chemistry in PDF only on Docsity! 1 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W Short Answer Drawing Instructions: Draw structures corresponding to each of the given names. 1. Draw: tetrahydrofuran 2. Draw: 12-crown-4 3. Draw: 1-isopropoxycyclopentene 4. Draw: allyl benzyl ether 5. Draw: diethyl ether 6. Draw: 3-methyl-1-butanethiol 7. Draw: cyclopropyl ethyl sulfide IUPAC Naming Instructions: Provide proper IUPAC names. 8. Name: 9. Name: 10. Name: Exhibit 18-1 Consider the reaction below to answer the following question(s). 2 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W 11. Refer to Exhibit 18-1. Write the complete stepwise mechanism for the reaction. Show all intermediate structures and all electron flow with arrows. 12. Refer to Exhibit 18-1. Mechanistically, the Williamson ether synthesis outlined above is: a. an E1 process b. an SN1 process c. an E2 process d. an SN2 process 13. Refer to Exhibit 18-1. Alternatively, cyclopentyl methyl ether may be synthesized from cyclopentene. Outline a synthesis of cyclopentyl methyl ether from cyclopentene. 14. Diphenyl ether is inert to cleavage by HI or HBr. Explain. 15. Write the complete stepwise mechanism for the reaction below. Show all electron flow with arrows and draw all intermediate structures. Exhibit 18-2 Consider the data below to answer the following question(s). Acetals are a special class of ethers which have two ether linkages at a single carbon. Tetrahydropyranyl ethers are acetals that are easily cleaved with mild aqueous acids at room temperature to yield alcohols. 16. Refer to Exhibit 18-2. Draw arrows showing the electron flow for this reaction on the structures provided below. 5 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W 24. 25. 26. 27. 28. 29. 30. 6 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W 31. 32. 33. 34. 35. Propose a synthesis of 1,4-dioxane, starting from 1,2-dibromoethane as the only source of carbon. 36. Choose the best reagent for carrying out the following reactions from the list below. Place the letter of the reagent(s) in the box over the reaction arrow. Use only one letter per box. 7 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W A. NaH, then CH3I B. NaOCH3, CH3OH C. m-ClC6H4CO3H D. CH3MgBr in ether, then H3O + E. warm H2SO4/H2O F. Hg(O2CCF3)2, CH3OH G. H2/Pd H. PCC, CH2Cl2 I. Cl2, H2O J. LiAlH4 in ether, then H3O + 37. Complete the synthetic sequence below by drawing the structures of the reaction in the boxes provided. 38. Show how the ether below could be prepared from toluene and any other necessary reagents. Show all reagents and all intermediate structures. 39. Propose a synthesis for the following compound using benzene or toluene and any other reagents necessary. Show all major intermediate compounds that would probably be isolated during the course of your synthesis. 10 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W a. 6 b. 4 c. 9 d. 5 e. 7 f. 8 ____ 47. Consider the following species. Atoms other than carbon and hydrogen are labeled. Which of the following would be produced upon treatment with I2,? a. b. c. 11 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W d. ____ 48. What is the product formed upon treatment of the following substance with hydrogen peroxide at room temperature, followed by treatment with a peroxyacid? Atoms other than carbon and hydrogen are labeled. a. b. c. d. ____ 49. Which of the following will undergo rearrangement upon heating? a. 2-pentenyl phenyl ether 12 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W b. 1-propenyl 2-propenyl ether c. 2-butenyl phenyl ether d. All will undergo rearrangement. 15 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W PTS: 1 16. ANS: PTS: 1 17. ANS: The carbocation generated in the first step of the SN1 process is resonance-stabilized by the adjacent oxygen lone pairs. PTS: 1 18. ANS: Basic nucleophiles like ethoxide react with epoxides in a typical SN2-type process, so attack takes place at the less hindered epoxide carbon. 16 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W PTS: 1 19. ANS: PTS: 1 20. ANS: d PTS: 1 21. ANS: PTS: 1 22. ANS: PTS: 1 23. ANS: PTS: 1 17 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W 24. ANS: PTS: 1 25. ANS: PTS: 1 26. ANS: PTS: 1 27. ANS: PTS: 1 28. ANS: PTS: 1 29. ANS: 20 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W PTS: 1 39. ANS: PTS: 1 40. ANS: Ethyl hexyl ether or 1-ethyoxyhexane PTS: 1 41. ANS: o-mercaptotoluene PTS: 1 42. ANS: PTS: 1 43. ANS: 21 CHEM 2425. Chapter 18. Ethers and Epoxides; Thiols and Sulfides (homework) W PTS: 1 MULTIPLE CHOICE 44. ANS: D PTS: 1 45. ANS: B PTS: 1 46. ANS: F PTS: 1 47. ANS: C PTS: 1 48. ANS: A PTS: 1 49. ANS: D PTS: 1