ORGANOMETALLIC COMPOUNDS

Transcription

1 CEM 242 RGNMETLLIC CMPUNDS CP 14 SSIGN 1. What is the product,, that would be obtained from the following reaction sequence? C 2 Mg C C 3 C C C CC 2 C CC CC 2 C 2 C CC C C CC C C C CC 2 I III D. I E. 2. What would be the product, C, of the following reaction sequence? CC 2 Li ether CuI B CC 2 C 2 C. 2,6-Dimethylheptane 2,2-Dimethylpropane 2-Methylpentane D. 2,2,5-Trimethylhexane E. 2,2,6-Trimethylheptane 3. What would be the product,, of the following reaction sequence? C 2 C Mg N ether D 2 C 2 C. C 2C 2 D D. C 2C 2C 2D E. C 2C 2C 2D C 2 C D 4. The reaction of lithium diethylcuprate with 1-bromo-4,4-dimethylhexane yields:. 3,3-Dimethylheptane 3,3-Dimethyloctane 1-Ethyl-4,4-dimethylhexane D. Di-4,4-dimethylhexylcuprate E. None of the above 1

2 5. What is the product,, that would be obtained from the following reaction sequence? III D. I E. P 3 Li ( ) 2 C= N 4 Cl 10 o C I II III I 6. What would be the final product,, in the following reaction sequence? III D. I E. P 3 Mg, Et 2 3 heat I 7. What is the principal product(s) formed when 1 mol of methylmagnesium iodide reacts with 1 mol of p-hydroxyacetophenone? III D. I E. IMg MgI MgI C 4 MgI IMg I 2

3 8. What product(s) is/are produced in the 1:1 reaction of sec-butylmagnesium bromide with CC 2 C 2 C Mg? CC 2 C 2 CCC 2 Mg. CC 2 C 2 C C 2 C 2 Mg Mg CC 2 C 2 CC 2 C( ) 2 D. CC 2 C 2 C ( ) 3 C CC 2 C 2 C CC 2 E. 9. What is the principal product of the following reaction: C C 2 CC 2 C 2 C 2 C 2C 2C 2Mg/ether; then 2?. C 2 CC 2 C 2 C 2 C 2 CC 2 C 2 C 2 CC 2 C 2 C 2 C 2 D. C 2 CC 2 C 2 C 2 C 2 E. C 2 C 2 C Which of the following synthetic procedures would be employed most effectively to transform ethanol into ethyl propyl ether?. Ethanol, then Mg/ether, then 3, then Na, then C 2 Ethanol, then Mg/ether, then C, then 3, then Na, then C 2 Ethanol C 2C 2 2S 4/140 C D. Ethanol Na, then C, then 3, then, then Mg/ether, then C 2C 2 E. Ethanol 2S 4/180 C, then C 2C 2 3

4 11. What compound(s) result(s) from the reaction of C 2C 2Mg with C 2C 2C 2C 2 (1:1 mole ratio)? ( C 2 C 2 ) 2 CC 2 C 2 C 2. C 2 C 2 CC 2 C 2 C 2 C 2 C 2 C 2 CC 2 C 2 D. C 2 C 2C 2C 2C 2Mg E. C 2 CCC 2 C 2 C 2 C 6 5 C 2 C 2 C 12. Your task is to synthesize through a Grignard synthesis. Which pairs of compounds listed below would you choose as starting materials? C. 3 C 2 C 2 and CC 6 5 C 2 C 2 C and C 6 5 C 2 C and C 6 5 C D. More than one of these. Which ones? E. None of these 13. Which combination of reagents is to be preferred for the synthesis of 2,4-dimethylhexane by the Corey-Posner, Whitesides-ouse procedure?. Lithium diisobutylcuprate sec-butyl bromide Lithium dimethylcuprate 2-bromo-4-methylhexane Lithium dimethylcuprate 4-bromo-2-methylhexane D. Lithium diisopropylcuprate 1-bromo-2-methylbutane E. Lithium di(2-methylbutyl)cuprate isopropyl bromide 14. Which of the following is the strongest acid?. RMgX Mg()X R D Which of the following is the strongest base?. RMgX Mg()X R D Which of these is the least reactive type of organometallic compound?. RK R 2g RLi D. R 2Zn E. R 3l 4

5 17. Which of the following would serve as a synthesis of racemic 2-methyl-1-phenyl-2-butanol? III D. ll of the above E. None of the above CC 2? I C 2 C 1. Et 2 C 2 MgCl 2. N 4 II C 2 C C 2 Mg 1. Et 2 2. N 4 III C 2 CC 2 MgI 1. Et 2 2. N Grignard reagents react with oxirane (ethylene oxide) to form 1 alcohols but can be prepared in tetrahydrofuran solvent. Why is this difference in behavior observed?. Steric hindrance in the case of tetrahydrofuran precludes reaction with the Grignard. There is a better leaving group in the oxirane molecule. The oxirane ring is the more highly strained. D. It is easier to obtain tetrahydrofuran in anhydrous condition. E. xirane is a cyclic ether, while tetrahydrofuran is a hydrocarbon. 19. Which of these compounds can be used to prepare the corresponding Grignard reagent?. CC 2C 2C 2C 2 () 3CCC 2C 2C 2 C=CC 2C 2 D. NC 2C 2 E. None of the above can be used to prepare the corresponding Grignard reagent 20. If the role of the solvent is to assist in the preparation and stabilization of the Grignard reagent by coordination with the magnesium, which of these solvents should be least effective? III D. I E. C 2 C 2 ( C 2 ) 3 N (C 2 ) 4 C 2 C 2 I 21. Which of these is most likely to be a successful synthesis of an organometallic compound?. C 2C 2Mg LiCl C 2C 2Li MgCl 2 C 2C 2C 2Li ZnCl 2 (C 2C 2C 2) 2Zn 2 LiCl 3 (C 2) 2g 2 lcl 3 2 (C 2) 3l 3 gcl 2 D. (C 2) 3l 3 NaCl 3 C 2Na lcl 3 E. () 2Cu Mg 2 () 2Mg Cu 2 5

6 22. What is the product of the following reaction? 1) 3) 1) 2 Mg 2) 3 2) 4) Phenylnaphthalene, shown below, can be prepared in over 80% yield by one of the reactions below. Which one? C 6 6, lcl 3 1) 3) Cl C 6 5 Mg diethyl ether C 6 5 I (C 6 5 ) 2 CuLi 2) 4) diethyl ether C 6 5, lcl 3 EXTR CREDIT 24. Which Grignard synthesis will produce an optically active product or product mixture? Mg. ClMg MgI D. MgI E. 3 C Mg 25. What would be the major product of the following reaction?. (R)-3-ethyl-5-methylheptane (R,S)-3-ethyl-5-methylheptane (S)-3-ethyl-5-methylheptane D. (3R,5S)-5-ethyl-3-methylheptane E. (3S,5R)-5-ethyl-3-methylheptane Cl Li, Et 2 CuI 6

7 NME DTE NSWER SEET CEM 242 CP 14 SSIGN SPRING