University:
Amherst College
Course:
CHEM 221 | Organic Chemistry I
Academic year:

2009
Views:

149

Pages:

4
Author:

Emilia Hernandez

Chem 21 Homework set 12 End-of-chapter problems from Hornback: problems listed on HW set 11 are still relevant... Ch 11: 32 - 37, 38 (of course, your syntheses must (not "may") produce racemic mixtures), 39 - 54. 1. Draw the products, including stereochemistry. Indicate any products that are enantiomers or diastereomers. Try to resist the urge to show stereochem where it isn't relevant. (a) CH2I2 1. mCPBA Zn(Cu) 2. H3O+ (b) 1. CF3CO3H 1. O3 2. aq. HO– 2. Me2S (c) 1. O3 Br3CH NaOH 2. Me2S H2 1. O3 Pd 2. Me2S (d) (e) HCl (excess) Ph C C Br2 H (1 equiv) (f) D2 Lindlar's catalyst Li Ph C C H NH3 (g) 1. Sia2BH 2. H2O2 aq HO– Ph C C H H+, Hg2+ H2O 2. A mystery alkene, C8H14, reacts with bromine to form cis-1,2-dibromocyclooctane. When the mystery compound is treated with OsO4, then aqueous sodium sulfite, the product is trans1,2-cyclooctanediol. Draw the mystery alkene. Include stereochemistry if you think it's relevant. (hint: you do think it's relevant.) 3. Write the mechanisms of these acid- and base-catalyzed tautomerizations. mechanisms are requested) OH (4 separate O (a) H+, H2O (b) HO–, H2O OH (c) H+, H2O O (d) HO–, H2O 4. Suggest a synthesis of each compound below from acetylene. (a) (b) HO O (c) (d) D Ph D 5. Suggest syntheses of the racemic compounds below starting from diphenylacetylene, PhCCPh. Pay attention to stereochemistry (as always, you may need to consider conformations other than those drawn to find a viable synthetic route). (a) (b) (c) Br Ph D D Ph Ph Cl Cl Ph Br Ph Ph Chem 21 Fall 2009 HW set 12 30 points; due Wed, Dec 9 Name _________________________________________ This is the last graded HW. Those desperate for points can do the extra set attached to the end of HW set 7 (originally due Nov 4), but, as before, this has to be done right or it's a waste of time, so no partial credit — turn this in by Mon, Dec 14, 11:00a. 1. Draw the products of the 6 reactions below, including stereochemistry where appropriate. 1. NaNH2 2. CH3CH2OMs 1. HBSia2 Br2 (1 equiv) 1. NaNH2 2. H2O2 H2O, HO– 2. CH3OD D2 Lindlar's catalyst 1. NaNH2 2. tBu–Br (careful!) 2. Acid-catalyzed hydration of allene (below) produces acetone. Write the mechanism of the reaction, illustrating each step clearly with curved arrows. H2C C CH2 H+ H2O O 3. Suggest two different syntheses of the diol below starting from diphenylacetylene. HO Ph Ph OH 4. Suggest a synthesis of (Z)-1-deuterio-5,5-dimethyl-1-hexene from acetylene. (Think carefully about how to get that D in the proper place.) D

Chemistry 21 Homework set 12

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