7,\"Reduction of Camphor\" Experiment (i) The products obtained from reduction o

Question

7,"Reduction of Camphor" Experiment (i) The products obtained from reduction of camphor by NaBH4 produces two products, Borneo! and isoborneol, which one is a major product (1 point) and explain your answer in detail. (4 points) 8. (Extra Credit) Draw a mechanism of the Dehydration of Cyclohexanol of reaction below. (Spo rts) Is it SNI, SN2, E1, or E27 (2 points) What is a byproduct? (3 points) 9, where do the following functionalities occur in a NMR spectrum (2pts each answer 5 points) a. alkyl b, alkyne, c. ether d, alcohol e. alkene £ aldehyde carboxylic acid h. aromatic protons 10. Analyze the attached NMR and identify them lecule (10pts) Use the degree of unsaturation formula to help determine a structure (5 points) g.

Explanation / Answer

5. Grignard reaction

a. Grignard reagent is a highyl reactive reagent which reacts with moisture immediately and gets deactivated. Hence it is important to use absolutely anhydrous condition for the reaction.

b. with 4.1 mmol of bromobenzene we would need = 4.1 mmol x 157.01/1.491 x 1000 = 0.432 ml

c. product yield (theoretical) = 4.1 x 260.33/1000 = 1.067 g

Percent yield = 0.625 x 100/1.067 = 58.6%

TLC

a. To get plate 3 from 2, we would use, 8 : 2 ratio of diethylether to dichloromethane solvent system. Dichlomethane is more polar than ether and so in plate 2, we have used large excess of dichlormethane and spots move to the top.

b. Rf of crude = 0.25

Rf of product = 0.4

2) Interpretation of spectrum

formula = C8H8O2

degree of unsaturation = 5

IR

3000-3100 cm-1 for sp2 =C-H stretch

2850-2950 cm-1 peaks for aliphatic C-H stretch

1720 cm-1 for C=O stretch

1500-1620 cm-1 for aromatic C=C stretch

1H NMR

3.9 ppm (singlet, 3H) for CH3 next to oxygen

7.4-8.0 ppm (multiplet, 5H) for phenyl protons

Possible structure

C6H5COOCH3

9. Shifts in NMR for

a. alkane : 2850-2950 cm-1

b. alkyne : 2250 cm-1 and 3100 cm-1

c. ether : 1400-1500 cm-1

d. alcohol : 3200-3500 cm-1

e. alkene : 3000-3100 cm-1 and 1620-1680 cm-1

f. aldehyde : 1730 cm-1, 2720 cm-1 and 2850 cm-1

g. carboxylic acid : 2500-3200 cm-1

h. aromatic products : 3000-3100 cm-1, 1500-1600 cm-1

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