Chemistry 2321 OLD TEST QUESTIONS

Transcription

1 Test No. 4 hemistry 2321 OLD TEST QUESTONS Professor M. Pomerantz Select the proper UPA name for the compounds shown ,3-bromo-4-methylheptane 2,3-dibromo-4-methylhexane 2,3-bromo-4-methylhexane 2,3-dibromo-4-methylheptane 2,3-dibromo-5-ethyl-4-methylpentane 2. l ( ) 3 cis-1-chloro-2-isopropylcyclopentane trans-1-tert-butyl-2-chlorocyclopentane trans-1-chloro-2-isopropylcyclopentane cis-1-tert-butyl-2-chlorocyclopentane trans-1-isopropyl-2-chlorocyclopentane 3. l bromo-3-chloro-4-methylheptane 2-bromo-3-chloro-4-propylpentane 2-bromo-3-chloro-4-methylhexane 6-bromo-5-chloro-4-methylheptane 2-bromo-3-chloro-5-ethyl-4-methylpentane 4. ( ) 2 cis-1-iodo-2-isopropylcyclopentane trans-1-isopropyl-2-iodocyclopentane trans-1-iodo-2-isopropylcyclopentane trans-1-iodo-2-isobutylcyclopentane cis-1-isopropyl-2-iodocyclopentane 5. Which of the following is the most stable carbocation Which of the following is the most stable carbocation

2 Page 2 - hemistry Old Test Questions - Test No n the free radical chlorination of 2,3-dimethylbutane the two products shown are formed in equal amounts. alculate the relative reactivity of a tertiary hydrogen compared to a primary hydrogen. l l 2 2 l + hν 5 : 1 1 : 6 6 : 1 3 : 1 1 : 5 Given the following reactions: Na solvent Na. 2 O + Na + Na solvent 2 5 O Na solvent Na V. 2 + Na solvent Na V. 2 + Na 2 5 O solvent 8. Which of the above is the fastest reaction V V 2 + Na 9. Which of the above will not occur only both and V only all will occur V only 10. Which of the following reactions is significantly faster than the others O + 2 O + 2 O O + 2 O + 2 O O + l 2 O l + 2 O 2 O O + 2 SO O all have essentially the same rate

3 Page 3 - hemistry Old Test Questions - Test No. 3 What reagent(s) can be used to carry out the following reactions without major side reactions O Na / SOl 2 2 / l 4 / NBS / / P / l 4 / NBS / l 4 / hν P 3 Na / 13. D 1) NaN 2 ; 2) D 2 O 1) KO / EtO; 2) D 2 / Pd/ 1) KOt-Bu / t-buo; 2) D 2 / Pd/ 1) Mg / Et 2 O; 2) D 2 / Pd/ 1) Mg / Et 2 O; 2) D 2 O Given the following reactions:. O 3 PO 4 2. OTs 2 5 O O 2 5. V. OO 2 2 OAc + 2 OAc DMF 2 OTs + NaN solvent 3 2 N V. KO O An E2 reaction is: V V 15. Reaction(s) which involve carbocations are: and, and V V, and V, and

4 Page 4 - hemistry Old Test Questions - Test No Which of the following reactions, if any, is significantly faster than the others 2 5 O + 2 O O O O O O O + l O O + 2 SO 4 all have essentially the same rate 2 5 l + 2 O + 2 O What is the major organic product from the following reactions 17. (S)-2-iodobutane + NaN N 2 N 2 Solvent 2 N N 2 an equal mixture of b and d Li u pentane u Li u Li ( ) 2 l 2 2 ( ) Na EtO ( ) 2 2 ( ) 2 2

5 Page 5 - hemistry Old Test Questions - Test No (1 mol a 1:3.5:5 ratio of b:a:c approximately equal amounts of a, b and c 21. KO l EtO approximately an equal mixture of c and d Li u pentane u u l KOt-Bu t-buo approximately equal amounts of a and b 24. Na EtO : 50 mixture

6 Page 6 - hemistry Old Test Questions - Test No O (R)-absolute configuration (R)-absolute config. only (S)-absolute config. only 2 5 almost completely racemic optically active almost completely racemic Mg OO ( 2 5 ) 2 O 2 2 O 2 O 2 O OTs Na this absolute configuration both b and c 28. Given the following E2 elimination reaction: D 2 2 l 2 5 ONa 2 5 O D 2 = + D= 2 A B... The ratio of A:B in the product will be approximately: 7:1 only A is formed 1:7 only B is formed 1:1

7 Page 7 - hemistry Old Test Questions - Test No Which of the following is NOT an oxidation 4 O 4 l O 2 = = 2 2 O 2 = Provide a step-by-step mechanism (show each step separately) for the following reaction. OTs 2 O O 31. Provide a step-by-step mechanism (show each step separately) for the propagation steps only for the bromination of propane to give 2-bromopropane hν Show step-by-step (include reagents and solvents/conditions where crucial) how you would convert the compound given to the product shown. You can use any stable organic molecules containing ONE or TWO carbon atoms in addition to the starting compound, any inorganic reagents and any solvents. Write clearly and TNK!!! Remember not to use reactions which give large amounts of undesired side products O l