Chemistry 251/253

Homework 1

INSTRUCTIONS

Answer Form

Back Up Answer Form (for emergencies only)

When you click the Answer Form button, a new window containing an Answer Form will open. Click the Load JavaGrins link in this new window to open a JavaGrins chemical structure drawing window. Arrange the JavaGrins drawing window, the Answer Form window, and this window so that you can go back and forth between all three. For questions that require SMILES, click the mouse in the appropriate text field on the Answer Form, then click on the link called Paste: SMILES. Use stereochemical SMILES for those questions marked with an *. For multiple choice and fill-in-the-blank questions, type your answer in the appropriate text field of the Answer Form.

This assignment is worth 30 points. After you have completed all the questions, fill in your first and last names along with your personal ID number and click thebutton. After you submit your work, you should receive confirmation that it has been received. Record the confirmation number. It is the only way you can prove that you submitted your assignment.

Note- NMR spectra are available for those questions with numbers shown in blue. Also, you should measure the heights of the integration curves to the nearest mm. Areas of certain spectra have been enlarged to make splitting patterns easier to read. The integration of an enlarged area will not be proportional to that of an unenlarged area.

2. How many of the following alcohols would be oxidized by treatment with CrO₃/H₂SO₄/H₂O?

3. Oxidation of an alcohol with aqueous chromic acid produced a compound that gave the attached ¹H-NMR spectrum. Draw the structure of this alcohol.

4. Draw the structure of the product of the following sequence of reactions:

5. Draw the structure of the product of the following sequence of reactions:

6. Draw the structure of the alkene that is best suited for the preparation of (CH₃)₂CHCH₂CHO.

7. Draw the structure of the alkene that you should use as a starting material in the preparation of.

8. Select the species that is most basic:

9. What is the number of the carbon atom that would be deprotonated in the following reaction?

10. How many of the following compounds would not react with PCC?

11. How many of the following compounds would not form an enolate ion when treated with aqueous NaOH?

12. Draw the structure of the product of the following reaction: Assume that all the bonds in the product are covalent.

13.The generalized reaction RLi + R'H ==> RH + R'Li is called transmetallation. What is the equilibrium constant for the following transmetallation reaction?

14. Draw the structure of the product of the following reaction:

15. Draw the structure of the major product of the following reaction:

16. Al Keene isolated an unknown compound from a wad of bubble gum he found stuck under the chair in his organic chemistry class. Out of curiosity Al decided to run some tests on the gum to see if he could determine its composition. He observed that a sample of the gum immediately decolorized a solution of Br₂ in CCl₄. When he treated another portion with aqueous sulfuric acid, Al obtained two new compounds, one of which turned an acidic aqueous solution of CrO₃ from orange to green, the olther of which did not. The compound that turned the chromic acid solution green gave the attached ¹H-NMR spectrum. Draw the structure of the compound that decolorized the Br₂ in CCl₄.

17. Draw the structure of the carbanion that would be formed by a kinetically controlled deprotonation of .

18. Draw the resonance structure that makes the most important contribution to the enolate ion that is formed when is deprotonated under thermodynamically controlled conditions.

19. Hexadeuteroacetone, a useful solvent for H-NMR work, may be prepared by treatment of acetone with a strong base in D₂O: .

Draw the structure of the deuterated product that would be formed in the following equilibrium: (You must show deuterium atoms explicitly in JavaGrins.)

20. What is the equilibrium constant for the following reaction?

21. What is the equilibrium constant for the following reaction?

22. Draw the structure of the alkene that is best suited for the preparation of by a reaction sequence involving hydration followed by oxidation.

23. Select the best description of the following reaction sequence:

24. How many of the following alcohols could you prepare satisfactorily by a hydroboration/oxidation sequence with an appropriate alkene?

25. The oxidation of produced a compound that gave the attached ¹H-NMR spectrum. Draw the structure of this compound.

26. Polly Ester performed the following reaction sequence successfully: However, she used up all of the 3-phenyl-1-butene when she ran the reaction. This was unfortunate because Polly's sister Ethyl needed some of this alkene for her own purposes. So Ethyl ran the following reaction sequence in order to convert some of Polly's 3-phenyl-2-butanone back to 3-phenyl-1-butene:, where [H] is a generic representation for a reduction reaction. It was also unfortunate because Ethyl did not isolate any of the desired 3-phenyl-1-butene she needed. Draw the structure of the material that Ethyl did obtain.

27. The reactionis A. an oxidation B. a reduction C. neither an oxidation nor a reduction.

28. Draw the structure of the compound with the lowest MW that has the empirical formula CHO₂ in which the oxidation level of the carbon(s) is +3.

29. An unknown compound, which was a solid at room temperature, contained 27.3% C. The ¹³C-NMR spectrum contained one signal. The compound was completely resistant to oxidation. Draw a structure that is consistent with this information. Note- carbon dioxide is not a solid at room temperature.

30. Draw the structure of the alkene that is best suited to the preparation of by a reaction sequence involving hydration followed by oxidation.