Best Reagent or Sequence of Reagents

1. Choose the best reagent or sequence of reagents from the list provided below to carry out the following synthetic transformations. Place the letter of your response to the left of the reaction. ( 9 pts.)

a. PBr3 d. SOCl2, pyridine

b. HCl(gas), ether e. HBr(gas), ether

c. 1. Mg, ether f. 1. Mg, ether
2. D2O 2. NBS

2. Provide structures for the reactants, intermediates or products, as indicated, in the following reactions. Draw the structures in the box provided. (28 pts.)

3. Draw the products of the following reactions. Clearly indicate the stereochemistry where important (3 points each for a total of 30 credits).

4. Consider the reaction below to answer the following questions. Place a circle around your choice. (12 pts.)

1. Compound B is the:
a. SN2 product
b. SN1 product
c. E2 product
d. E1 product

2. Compound C is the
a. SN2 product
b. SN1 product
c. E2 product
d. E1 product

3. The mechanism involved in the formation of compound B is ?
a. SN2
b. SN1
c. E2
d. E1
4. The rate law that is obeyed or involved in the formation of compound B is:

a. rare = k[RCl][H2O]
b. rare = k[RCl]
c. rare = k[RCl][H2O][ROH]
d. rare = k[ROHl][H2O]

5. Draw the structure of the major organic product(s) for each of the following reactions. Indicate the stereochemistry for each reaction when appropriate. (24 pts.)

6. Consider the following two reactions below to answer the following questions. (15 pts.)

4. The alkyl bromide starting materials in these reactions are classified as:
a. 30
b. 20
c. 10
d. 40

5. The solvent in these reactions is:

a. Non-polar aprotic
b. Polar aprotic
c. Polar protic
d. Non-polar protic

6. The nucleophile in these reactions is:

a. K+
b. Alkyl group
c. Br-
d. I-

7. Which reaction is faster? A or B ? Briefly explain.

8. The mechanism for these reactions is:

a. SN2
b. SN1
c. E2
d. E1

7. Please draw structures corresponding to the following names. Show proper number of hydrogens (condensed form, such as CH3 is fine) about each carbon atom except for cyclic structures that may be shown in polygons. (12 pts.)

(1) (E)-2,3-dibromo-2-butene (2) p-bromobenzoic acid

(3) (2R, 3S)-dibromobutane (4) (S)-2-bromobutane

3. Please answer the following questions.(11 pts.)

(1) Determine whether the following structure is the R- or S-configuration. Show how priorities are determined.

(2) Draw the structure of the enantiomer and of one diastereomer of the molecule shown; use dashed and/or solid wedges.

3. For the molecule shown below in planar form, draw the most stable chair conformation for the cis isomer

8. Please complete the following reactions by supplying the missing reactants or product(s) as indicated by a ? mark. Do not balance and do not show inorganic products or mechanisms. (30 pts.)

?

9. Matching. In the space provided in column 1, write the letter of the statement in column 2 that answers each part given in column 1. There is only one correct answer for each part in column 1, but statements in column 2 may be used more than once and some may not be used at all. (12 pts.)

Column 1 Column 2
__________________________ _________________________

___ A structural isomer of pentane A. SN1

___Carbocations are involved in this elimination B. SN2
mechanism

___Substitution occurs with racemization by this C. are enantiomers
mechanism

___R and S isomers D. (CH3)2CHCH2CH3

___ Involves syn addition to carbon-carbon E. catalytic hydrogenation
double bond

___An elimination reaction of alkyl halides in the F. equal mixture of enantiomers
presence of a strong base that involves a concerted
mechanism G. E1

H. E2

I. CH3CH2CH2CH(CH3)2

10. A hydrocarbon A with a molecular formula of C6H12 reacts with 1 equivalent of H2 in the presence of Pd/C. When treated with O3 followed by Zn/H3O+, two fragments are produced; one is propionaldehyde (see below) the other is a ketone B. Upon treatment with OsO4 followed by NaHSO3, A is converted to a diol C. Draw the structures of A, B and C (3 points each for a total of 9).

11Please answer the following questions.
a.) Draw all of the unique Newman projection formulas of ClCH2CH2Cl (8 points).

b.) Label your drawings as either staggered, eclipsed, and if applicable, anti or gauche (4 points).