Chem 220 - Organic Chemistry

Problem Set 9

Chapters 10: The Chemistry of Alcohols and Thiols

Due: November 14, 2011xxxxxxxxx

Some of the problems in the alcohol module in ORGO will serve to review the chemistry of this chapter. As you master the chemistry of alcohols, you should try the Web of Reactions. You will not be able to do all of them.

1. How many grams of KMnO4 in aqueous KOH are required to oxidize 30 grams of 1-pentanol to pentanoic acid (valeric acid)? [Note: MnO2 is the reduction product of permanganate. This is a redox reaction from Gen. Chem. Go here for help. Derive the balanced equation and show your work.].

2. Optically active compound A (C6H14O) reacts with tosyl chloride/pyridine to form B. Treatment of B with KOH solution affords optically inactive compound C. Ozonolysis and dimethyl sulfide reduction of C provides D (C4H8O) and E. Compound D is inert toward aqueous chromic acid. Compound C is more stable than its stereoisomer F. What are the structures A-F? What is not known about A? Show your reasoning. How would you efficiently prepare (±)-A from F?

Paul Sabatier

(1854-1942)

Co-Nobel Prize in Chemistry (1912)

Catalytic Hydrogenation

Victor Grignard

(1871-1935)

Co-Nobel Prize in Chemistry (1912)

Organomagnesium Compounds

3. Provide reagents for the completion of each of these reactions. No non-selective reactions. Justify your answers.

4. A laboratory bottle has the label "C5H11Br". A student decides to run some reactions on the contents of the bottle to determine the structures of the compound A. What are the structures A-F? Show your reasoning. [Hint: Draw all of the structures of C5H11Br. Eliminate non-contenders? Only the major product in the formation of C should be considered.]

5. Consider problem 10.56 on pg. 480. Studies on the mechanism of Swern oxidation provide the results of two experiments.

a) How do these results compare with the mechanism shown in the Study Guide?

b) The Swern oxidation does not mix everything together as you may conclude from the text. There are three steps involved. Using the first reaction, show the products formed in each step with a mechanism for each. [Hint: Step 1 produces CO and CO2.]