Chemistry Department

 

University of Alberta

           

CHEM 263 B2

 

Exam I

 

Thursday, February 12, 2009

 

1.    The IR and ¹H NMR spectra of a compound of molecular formula C₅H₁₀O₂ are given below. 

 

SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ (15-01-09)

 

Here is the spectrum amplified between 0 and 4 ppm:

 

a.    Calculate the degree of unsaturation. (1 point)

 

b.    List the possible functional groups gleaned from the molecular formula. (3 points)

 

c.    What is the oxygen-containing functional group that the IR spectrum shows to be present in the unknown? (1 point)

 

d.    Propose a structure for this compound. (10 points)

           

2.    Sketch the expected ¹H NMR spectrum of the following compound:

 

 

3.    Benzoquinone is a very reactive dienophile.  It reacts with 2-chloro-1,3-butadiene to give a single product, C₁₀H₉ClO₂, in 95% yield.  Draw the structure of this product.

 

 

4.    When either 1-chloro-3-methyl-2-butene or 3-chloro-3-methyl-1-butene is treated with moist Ag₂O, in addition to the formation of AgCl, mixture of alcohols is obtained:

 

 

a.    Propose a mechanism to account for the formation of the two products.

 

b.    Explain the relative yields of the two products.

 

 

5.    Explain the observed rate of reactivity of the following chlorides in an S_N1 reaction:

 

 

 

 

6.    Provide a synthetic pathway for the following transformation:

 

 

7.    Give the structure(s) of the principle organic products of the following reactions:

 

a.     

 

 

 

b.     

 

 

 

c.