Predict the product of the following aldehyde/ketone syntheses.
(c)

Show how you would accomplish the following synthetic transformations. Show all intermediates.

j. trans-hex-2-ene → cis-hex-2-ene

Predict the products of reaction of pent-1-yne with the following reagents.

j. NaNH₂

k. H₂SO₄/HgSO₄, H₂O

l. Sia₂BH, then H₂O₂, ^–OH

Draw the ketone(s) you would expect to form by treating the following alkynes under the conditions of hydroboration–oxidation: (a) 6-methyloct-1-yne, (b) 1,10-dicyclohexyldec-5-yne, and (c) 5-phenylhex-2-yne.

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For the alkynes shows here, show the product(s) expected to form when treated under the following conditions: (vii) 1. BH₃ 2. H₂O₂, NaOH. If you expect two products, show both.

(c)

How can the following compounds be prepared using ethyne as the starting material?

a.

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