Problem Set 9

Chem 220

Due : Monday, November 10, 1997

Chapter 12

Study the examples in Alkynes on ORGO before doing this PS. Answer the questions

before looking at the answers.

1. Compound A (C10H20) reacts with Cl2 to form B (C10H20Cl2). Treatment of B with t-

BuOK/t-BuOH gives (Z)-5-chloro-5-decene C. What are the structures of A and B and

show how they are formed?

2. Design a synthesis of (Z)-3-hexen-1,6-diol from organic compounds having two or fewer

carbons.

3. Compound A (C8H14) reacts with NaNH2 to form B (C8H13Na). A is formed

from B when B is added to water. B reacts with C (C6H13Br) to form D

(C14H26). Treatment of C with Mg in ether followed by addition of ethylene

oxide forms n-octanol. When D is exposed to Li/NH3, compound E (C12H24) is

formed. Bromination of E gives a meso compound F. What are the structures of A-

F and show how they are formed?

4. Disparlure (1), is the sex attractant of the female gypsy moth. It is an optically active

compound. Show how to synthesis racemic 1 from 5-methyl-1-hexene, 1-octanol, and

any other carbon compound.

5. Demonstrate your knowledge of acid/base reactions and resonance to show how 2-hexyne is

converted to 1-hexyne (SHK, pg. 308). 1,2-Hexadiene (CH3CH2CH2CH=C=CH2) is an

intermediate in the reaction. Why is the reaction driven to the right with stoichiometric base and not

catalytic base?

6. Why is (Z)-cyclohexene stable and (E)-cyclohexene and cyclohexyne are not?

7. Compound A, (C4H6) reacts with catalytic HgSO4 in the presence of aqueous sulfuric acid to form

B. Compound A does not react with NaNH2 in NH3 at -33 oC. 2,2-Dimethyl-3-pentanol

rearranges in the presence of sulfuric to give C (C7H14). Ozonolysis of C gives two ketones: D

(C3H6O) and B. What are the structures of A-D and how are they formed?