Organic Chemistry II
	Professor Carl C. Wamser
Chem 335 - Winter 2008	Exam 2 Answer Key

1.  (15 points)  Write clear structures for each of the following:

a)   (Z),(R)-4-hexen-2-ol

b)  a chromate ester

c)  an isobutyl Gilman reagent

d)  the periodic acid cleavage products from 1,2-propanediol

e)  sodium 4-nitrobenzenethiolate

2a.  (5 points)  Draw a typical quartet from a proton NMR spectrum and show where the chemical shift (d) and the coupling constant (J) would be measured.

2b.  (5 points)  Give a specific example of the 18-electron rule, explaining how your example fits the rule.

2c.  (5 points)  The formation of a vicinal diol using tBuOOH and OsO4 is a syn addition.
Illustrate what this means in terms of the stereochemistry of the product expected from cyclopentene. Draw the product(s) expected and designate stereochemistry with R and S.

2d.  (5 points) The formation of a vicinal diol using tBuOOH and OsO4 is a syn addition.
Illustrate what this means in terms of the stereochemistry of the product expected from
cis-2-butene.  Draw the product(s) expected and designate stereochemistry with R and S.

3.  (15 points)  Complete each of the following reactions by writing the structure of the expected product:

a)

b)

c)

d)

e)

4.  (20 points)  Show how to prepare each of the compounds below using Grignard coupling reactions for the C-C bond-forming steps.  All the carbons in the products must originate from alcohols having four or fewer carbon atoms.  You may use any needed reagents or solvents.

5.  (15 points)  Identify the unknown compound based on the data below.

molecular formula    C9 H10 O2

What is the calculated IHD? 5

1H NMR :
            a          9.9 ppm ,  1 H ,  singlet
            b          7.8 ppm ,  2 H ,  doublet
            c          6.9 ppm ,  2 H ,  doublet
            d          4.1 ppm ,  2 H ,  quartet
            e          1.4 ppm ,  3 H ,  triplet

Identify by letter on your final structure each of the H absorptions above.

How many different peaks would be expected for this compound in its 13C NMR spectrum?

7

6.  (15 points)  Identify the unknown compound based on the data below.  It has IHD = 0.

Mass spectrum:  molecular ion at  152  &  154   (approximately equal intensity peaks)
            additional peaks at  107  &  109  (equal intensity)
            largest peak at  59

13C NMR:   peaks at  70, 66, 30, and 15 ppm

1H NMR :
            a          3.7 ppm ,  2 H ,  triplet
            b          3.5 ppm ,  2 H ,  quartet
            c          3.4 ppm ,  2 H ,  triplet
            d          1.2 ppm ,  3 H ,  triplet

Identify by letter on your final structure each of the H absorptions above.

Identify each of the  13C  peaks by reference to your structure.

Identify each of the peaks in the mass spectrum.