9. Alkenes and Alkynes

Long, polarized bonds are also reducible in the same way that the C―C π bond of an alkyne is. Show a mechanism by which a C―Br bond might be reduced by sodium metal.

What are products of the following reactions?

c.

Show how you would convert

a. oct-3-yne to cis-oct-3-ene.

b. pent-2-yne to trans-pent-2-ene.

Predict the product of the multistep synthesis

Answer Problem 39, parts a–h, using 2-butyne as the starting material instead of propyne.

h. H₂/Lindlar catalyst

Answer Problem 39, parts a–h, using 2-butyne as the starting material instead of propyne.

g. excess H₂, Pd/C

What are products of the following reactions?

b.

What are products of the following reactions?

a.

What stereoisomers are obtained from the following reactions?

b.

What stereoisomers are obtained from the following reactions?

The following reaction was recently reported to have been performed electrochemically.

(a) Identify the reagent and a solvent that could have been used if this reaction was done traditionally.

(b) What safety and environmental hazards are improved or worsened when doing this reaction electrochemically?