Question

Write the products of the following sequences of reactions. Refer to your roadmap to see how the combined reactions allow you to "navigate"between the different functional groups. For example, in part (a) below, notice how the reaction sequence results in the conversion of an alkyne into a haloalkane in two steps.

Short answer

Answer: The final product of the given sequence of reactions will either contain an alcohol (-OH) group or a nitrile (-CN) group attached to the carbon skeleton, depending on the specific reagents used in the nucleophilic substitution step.

Step-by-step solution

Part (a): Alkyne to Haloalkane in two steps

Step 1 – Hydrogenation of Alkyne to Alkene: To go from an alkyne to a haloalkane, we first need to convert the alkyne into an alkene. This can be done through the process of hydrogenation. In this step, a hydrogen molecule (H2) is added across the triple bond of the alkyne, using a metal catalyst such as palladium (Pd) or platinum (Pt). Step 2 – Halogenation to convert Alkene to Haloalkane: Now that we have an alkene, we need to convert it into a haloalkane. This can be done through halogenation. In this step, a halogen molecule (e.g., X2, where X is a halogen like Cl, Br, or I) is added across the double bond of the alkene, resulting in the formation of a haloalkane.

Part (b): Continuing with the product from Part (a)

Step 3 – Nucleophilic Substitution Reaction: Continuing with the haloalkane from Part (a), we can perform a nucleophilic substitution reaction. In this step, a nucleophile (e.g., -OH or -CN) approaches the carbon attached to the halogen and replaces it, forming a new bond. A good leaving group such as a halogen is essential for this reaction to take place. Step 4 – Identify the product: Now that all the reactions have taken place, we can identify the final product of the given sequence. In this case, we began with an alkyne, converted it to a haloalkane, and then performed a nucleophilic substitution reaction to get our final product. Depending on the specific reagents used, the final product will either contain an alcohol (-OH) group or a nitrile (-CN) group attached to the carbon skeleton.