12-02 - 12/2/2009 How could a bromohydrin be prepared from...

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Unformatted text preview: 12/2/2009 How could a bromohydrin be prepared from styrene? Choose the correct reaction sequence for the preparation of styrene oxide from styrene. Br O H H OH Na :H O Br O Na :H A. OH Br Br ? Br Na :H OH Br Br O H styrene oxide styrene oxide Na :H Br H OH B. Are there any other syntheses of epoxides? R O O H O Using the curved arrow formalism show the bond making that transform the following intermediate into styrene oxide and the carboxylic acid. R O O H O ? OH RCO3H O Na :H Br RCO3H O Na :H Br OH Using the curved arrow formalism show the bond making that transform the following intermediate into styrene oxide and the carboxylic acid. R O O H O Using the curved arrow formalism show the bond making that transform the following intermediate into styrene oxide and the carboxylic acid. R O O H R O O H O RCO3H Na :H Br OH O O RCO3H Na :H OH Br 1 12/2/2009 Predict the major product of the following reaction. R O O H H CH3 + O H H H3C O R O H O H How could a single enantiomer be prepared as the R R major product? O H O O H H CH3 + O H H H3C O O H H O + CH3 H H O H H O + CH3 H H O H CH3 RCO3H CH3 CH3 RCO3H CH3 i A. i + ii B. ii + iii ii C. iii + iv iii D. i + iv iv E. ii + iv F. all A. i + ii i B. ii + iii ii C. iii + iv iii D. i + iv iv E. ii + iv F. all One strategy would be to use a chiral reactant. R(S) O H O O H H CH3 + O H H H3C O Predict the major product of the following reaction. R(S) O H (S(S-face) (R-face) (R- These two diasteriomeric transition states have different energies. O + CH3 H H CH3 O H H CH3 RCO3H O H / H2O O H H 2O OH OH OH O H OH OH O i A. i + ii B. ii + iii ii C. iii + iv iii D. i + iv iv E. ii + iv F. all A OH B C D E Predict the major product of the following reaction. OH Br H OCH 3 OCH3 OH Predict the major product of the following reaction. O H O CH3 O CH3 O H Br O O CH3 CH3 O CH3 CH3 O H / HO CH3 O H H O OCH3 Br OH OCH 3 Br OH O H O CH3 O O H CH3 O H OH OH OCH3 OCH3 OH OH OCH3 OCH3 OH OCH 3 OH OCH3 OH OCH 3 OH OCH3 A B C D A B C D 2 12/2/2009 An unknown compound A has the following properties: 1. The formula for A is C6H14O and the infrared spectrum shows a strong absorption at 3367cm-1. alkane OH 2. Treatment of A with acid results in the formation of an alkene B (C6H12) which upon treatment with BH3 followed by HOOH/ OH OH on least substituded carbon gives back compound A. 3. Alkene B reacts with H-Br to give an alkyl bromide C whose 1H NMR spectrum is shown below. 2 CH3 groups CH2-CH2 CH3-CH2 3. Treatment of alkyl bromide C with potassium t-butoxide gave a new alkene D that, upon treatment with O3 followed by zinc produced formaldehyde and 2-pentanone. Alkene D is 3-methyl-1-pentene. A. Very sure this is true C. Maybe this is true D. Maybe this is false F. Very sure this is false B. Somewhat sure this is true E. Somewhat sure this is false Alkyl bromide C must have the following structure. A. Very sure this is true C. Maybe this is true D. Maybe this is false F. Very sure this is false B. Somewhat sure this is true E. Somewhat sure this is false H H C O O O D 3. Treatment of alkyl bromide C with potassium t-butoxide gave a new alkene D that, upon treatment with O3 followed by zinc produced formaldehyde and 2-pentanone. 3. Treatment of alkyl bromide C with potassium t-butoxide gave a new alkene D that, upon treatment with O3 followed by zinc produced formaldehyde and 2-pentanone. Alkyl bromide C must be 2-bromo-2-methylpentane. A. A. Very sure this is true C. Maybe this is true D. Maybe this is false F. Very sure this is false B. Somewhat sure this is true E. Somewhat sure this is false 3. Alkene B reacts with H-Br to give an alkyl bromide C whose 1H NMR spectrum is shown below. Alkene B must be 2-methyl-1-pentene. A. A. Very sure this is true C. Maybe this is true D. Maybe this is false F. Very sure this is false B. Somewhat sure this is true E. Somewhat sure this is false 3. Alkene B reacts with H-Br to give an alkyl bromide C whose 1H NMR spectrum is shown below. O O D D 3 12/2/2009 Alcohol A must be 2-methyl-3-pentanol. A. Very sure this is true C. Maybe this is true D. Maybe this is false F. Very sure this is false B. Somewhat sure this is true E. Somewhat sure this is false What spin-spin coupling pattern would be predicted for HB? Assume the following spin-spin coupling constants JAB = 10 hz JBC = 5 hz JAC = 0 hz 2. Treatment of A with acid results in the formation of an alkene B (C6H12) which upon treatment with BH3 followed by HOOH/ OH gives back compound A. OH O B D Sketch the spin-spin coupling pattern predicted for HB based upon the following coupling constants. What is the spin-spin coupling pattern that would be observed for HB? A. doublet of triplets B. triplet of doublets C. doublet of quartets B. quartet of doublets JAB = 10 hz JBC = 5 hz JAC = 0 hz JAB = 10 hz JBC = 5 hz JAC = 0 hz What is the spin-spin coupling pattern that would be observed for HB? 3.2 ppm What is the spin-spin coupling pattern that would be observed for HB? 3.2 ppm JAB = 10 hz JBC = 5 hz JAC = 0 hz 5 10 JAB = 10 hz JBC = 5 hz JAC = 0 hz 4 12/2/2009 What is the spin-spin coupling pattern that would be observed for HB? 3.2 ppm Use the curved arrow formalism to show the bond breaking and bond making in the following reaction. JAB = JBC Br 5 ...
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