Question #1: Name the Following Aldehydes and Ketones

CHM 252 Organic Chemistry II NAME ______

Homework #3, Spring 2008

Due: Friday, April 4, 2008 by 5:00 pm

Question #1:
Name the following aldehydes and ketones.

Rank the compounds from MOST reactive (least stable) to LEAST reactive (most stable). Explain why you ranked them as you did.

Question #2: Draw the following aldehydes and ketones (with the correct stereochemistry where appropriate).

(a)  (S)-2-ethyl-5-chloropentanal

(b)  2,2,5,5-tetramethylcyclohexanone

(c)  (Z)-4-methyl-3-hexen-2-one

(d)  (3R, 5R) 3-chloro-5-methoxycyclopentanecarbaldehyde

(e)  4-isobutylacetophenone

(f)  (S)-2-methyl-5-oxoheptanal

Question #3: Complete each of the following reactions.

Question #4: For the completion problem generating D and E (question #3), answer the following questions/directives:

(a)  Work thru the mechanism that shows how the acetal is formed under acidic conditions

(b)  Once you have generated the TAI, it doesn't spontaneously revert back to the starting carbonyl -- why not?

(c)  What is the intermediate that forms after reaction with Mg, ether? What's its function? How does this intermediate react with the oxirane ring (show a mechanism)?

(d)  During the ACIDIC work-up for the Grignard reaction, the initial terminal alkoxide ion gets protonated AND the protecting group is removed -- show how the protecting group is removed by working BACKWARDS through the reversible steps that you produced in part (a)

(e)  Is this reaction an example of carbonyl addition or NAcS (nucleophilic acyl substitution)?

(f)  Experimentally, how is the reaction forced in either the forward or reverse directions?

(g)  Show the mechanism if we changed the initial conditions to p-toluenesulfonic acid and ethylene glycol.

Question #5: Starting with the structure from question #1d, complete the following concept map by providing the structures for compounds G-M.

Question #6: Provide a complete reaction mechanism showing the interconversion of I to J in question #5.

Question #7: Aspartame is used in artificial sweeteners such as NutraSweet and Equal. In fact, aspartame is 160 times as sweet as sucrose (table sugar). In order to simulate what happens in your stomach upon digestion, you proceed to the laboratory and place a sample of aspartame in round-bottom flask. You heat the sample at reflux for 1 hour in an aqueous HCl solution (pH = 2.5). What products do you expect to receive upon complete hydrolysis? Provide complete step-by-step reaction mechanisms for your hydrolysis reactions.

Question #8: Give the structures for each of the products A-M in the following reaction sequence.

Question #9: Synthesize each of the following starting from the given starting material and any 1-3 carbon-containing alcohols, alkynes, alkyl halides, amines, epoxides, aldehydes, ketones, or carboxylic acids. Assume all non-organic reagents are available.