topic6inclass3

topic6inclass3 - In Class Problem: List the following...

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Unformatted text preview: In Class Problem: List the following organic radicals in the order of increasing stability. H >_< . H H C.—H H>C=C—H H—(lz—céH H’ l H IL 1, l \L ’l l \V'\ ___° / \,,. cv—C#\l/ I. ~ . ._,__ / < L % (\U < / <C r w ll D it \ 0 SN reactions allow for interconversions of functional groups, which will be useful in further transformations. How would you prepare the following nitrile? >o "“ ON 5N2 reactions are also useful in preparing larger molecules from smaller molecules by alkylation of acetylide anions. The resulting alkyne can be transformed into other compounds. How would you prepare the following alkyne from starting materials with 7 or fewer carbon atoms? \ WW I 59 up 0 cuf— é / N“? B JLOH Ph REVIEW PROBLEMS Problem: Why does the following reaction not take place? CH3CHZCH3 + H0— ——+ CH3CHZCH20H +® / OKUQFJW [MK/Hg Prob/em: Explain why reaction of 1-bromopropane with potassium cyanide gives a mixture of CH3CHZCHZCN (major product) and CH3CHZCH2NC (minor)? Draw Lewis structures of the products and. nucleophiles. /\/(;r4—LLQ\) ————5/\/CN+/\/\L Q 'Cgmi CE») /\/ + r G) /0/‘( MN 0" {G320 Problem: How can you prepare the following two compounds from the appropriate alkyl bromide? (a) Methyl phenyl ether, Me-O-Ph Q) 0W olv\ j; "on E”? Q/ “‘3 :3” 3% Q U></\ “Lam: Problem: How could you perform the following synthesis? [An introduction to designing mult'i-step syntheses] N3 OH [:5 from (5 0V! ff N M ii}? ( 1 i: \3 :1 5 £3 + We Problem: Predict the structure of the product of the following reaction Cl /¢) IN“) 5‘1»; NaOH A9 J’ EtOH 9 5r“ z (a —‘_’ C6H1OS ) MA; JWMTHM/x nut (w or: /SH dioer mask , W Pnkerx M c \S i “9 / ‘3‘ (1714105 39 In Class Problems: Designate the nucleophile, the electrophile, and the leaving group for each of the following reactions. ' M7 \‘a’gpfi(\ ?H (2) Hz—C>/o\c</CH3 _.. Cl—IaoNH HSCO—CHz—i—CHs H3 CH3‘ W ' CHEM 2311 E3 Practice-iii (answers not provided) 1. (32 points) Circle the letter on the right which corresponds to the answer to each question. There is only one correct answer for each question. (i) Which of the following terms describes the reactivity of boron tribromide, BBT3? A. Bronsted-Lowry acid and Lewis acid A B. Bronsted-Lowry base and - .4 . - e B C. Lewrs scar! and not a = a sted-Lowry acr C D. Lewis base and not a Brransted-Lowry ase D (ii) What is the equilibrium constant (Keg) at 25 °C for a reaction with a AG° value of 0 kcal/mole. E E. —1 F. o G. 1 H. 1x103 F G H (iii) Which of the following is the correct order of increasing acidity (less acidic < more acidic)? l. CH4 < NH3 < H20 <CH3NH2 J. NH3 < CH4 < MeOH < HF J K. NH3 < CH4 < H20 < MeOH L. H20 < CH3COQH < i430+ < HCI K L (vi) During which of the following reactions did a rearrangement occur? M t—butanol —> 2-methylpropene M . ,3-dimethyl- -u .' o —-> ' N O. cyc o exene —> 1,2—dichlorocyclohexane O P. t-butanol —> t-butyl chloride P (v) Which of the following is wouid react most quickly in an 8N1 reaction with acetic acid? l'. (-UUlaHUl —) l-DUlyl CHIUHUB (v) Which of the following is would react most quickly in an 8N1 reaction with acetic acid? Q. methyl fluoride S. isopropyl chloride R. eth l chloride . I rt-butyl bromr (vi) Which of the following statements is not true regarding the reaction of 1° alkyl halides with good nucleophiles? . maxim - o nds on concentration of nucleo V. alkyl fluorides are unreactive W. large groups near the halide will not effect the rate X. the rate will be faster at higher temperatures (vii) Which of the following is the most reactive nucleophile? Y. tent—butyl cation Z. dimethyl ether AA. dimethylamine (viii) Which of the following anions is the strongest base? CC. CHgCOO‘ DD. HO’ EE. NHg' FF. Cl' BB. water XE<C ammo 88%;“ CC DD EE 2. (36 points). Provide the structure of products or reagents for each of the following reactions (8) (S)-2-bromooctane + I‘ C! + KCN Cl Product 0 B + t _......__.. r H OH I Reaoent I 3) Complete the following statements: (i) Reaction of (R)—1-bromo-3-methylhexane with sodium methoxide producesd; 2(8) / racemic methyl 3-methylhexyl ether (circle one) (ii) The rate of the above reaction depends on the concentration 0 alk l hall - / ' ' alltha :Hv (iii) Heating the above reaction will result in slower reaction circle one) (iv)The best solvent for this reaction would be water/ :Eexane / acetic acid (circle one) 3. (32 points). Conversion of 3-methyl-1-butane to 2-methylhexane requires three synthetic steps. Provide reagents and the structure of the two synthetic intermediates in the following scheme reagent a?" synthetic intermediate \ %/ )/\/ (b) With reference to structure, explain why the tosylate anion (shown at right) H 00 S 3 is a much better leaving group in 8N2 reactions than the hydroxide anion (HO')- 062 U? Q E70 (—— 0, Sg‘f‘: L» s. ~v o <f7 /: \\ > \ i — \ l}, o 09 J (c) With reference to structure, explain why acetonitrile, CHaCN, is a weaker base than ethylamine, CH3CH2NH2. 4/ @ demoed i) a §JIWA3J we! Wm ClscllN/tg W3 Cst U “W“LV (0M: W7» C(écqu/VJCLL (d) A student realizes that protonation of an alcohol makes the -OH into a better leaving group. Therefore, he suggested that reaction of 1-propanol, H2304 and trimethylamine would provide N,N,N-trimethyl-N-propylammonium hydrogen sulfate according to the following key mechanistic step. However, this process does not yield the product predicted here. Why not? OH H030? /\/ 2 —'* (-9 + H20 up sea1 3 ‘ (rial-Vt am} W 5M3 6»le FAA" JMNJ (Ms\ L: {imtvrflb The role of nucleophi/icity, leaving group ability, and substrate on SN processes. Which of the following proceed efficiently? H3C—Br “20 NaOH HBr H20 H20 ' ...
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This note was uploaded on 10/24/2010 for the course CHEM 2311 taught by Professor Tyson during the Spring '07 term at Georgia Tech.

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topic6inclass3 - In Class Problem: List the following...

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