10. Addition Reactions

What are products of the following reactions?

e.

The following functional-group interchange is a useful synthesis of aldehydes.

(a) What reagents were used in this chapter for this transformation? Give an example to illustrate this method.

(b) This functional-group interchange can also be accomplished using the following sequence.

Propose mechanisms for these steps.

For each of the following alkynes, draw the products obtained from (1) the acid-catalyzed addition of water (mercuric ion is added for part a) and from (2) hydroboration–oxidation:

a. 1-butyne 

What is the major product of the reaction of 1 mol of propyne with each of the following reagents?

e. aqueous H₂SO₄, HgSO₄

f. R₂BH in THF followed by H₂O₂/HO⁻ /H₂O

a. Explain why a single pure product is obtained from hydroboration–oxidation of 2-butyne, whereas two products are obtained from ­hydroboration–oxidation of 2-pentyne.

b. Name two other internal alkynes that yield only one product upon hydroboration–oxidation.

What are products of the following reactions?

d.

What hydrocarbon would you use to prepare the organoboron compound in Problem 14?