Synthesis of Alkenes and Alkynes

The video tutorial presents a synthesis challenge to convert trans 2-butene to cis 2-butene in three steps. The instructor explains that while this is not a practical lab problem, it serves as a thought experiment to explore reaction strategies. The process involves generating an alkyne through dihalogenation and elimination reactions, followed by selective hydrogenation using a Lindlar catalyst to achieve the desired Z alkene. The tutorial emphasizes the importance of understanding reaction mechanisms and applying them strategically.

What is the main goal of the synthesis problem discussed in the video?

• To synthesize a new compound from butene.

• To convert trans-2-butene to cis-2-butene in three steps.

• To convert cis-2-butene to trans-2-butene in three steps.

• To demonstrate the practical application of butene synthesis.

Why is the synthesis problem considered impractical?

• Because it requires expensive reagents.

• Because it produces a lot of waste.

• Because both trans-2-butene and cis-2-butene are readily available.

• Because it takes too long to complete.

What is the purpose of selective hydrogenation in this synthesis?

• To convert an alkene to an alkyne.

• To increase the reaction rate.

• To convert an alkyne to a Z alkene.

• To remove impurities from the reaction.

Which reagent is suggested for the dihalogenation process?

• Fluorine and acetone

• Iodine and ethanol

• Chlorine and water

• Bromine and CCl4

What is the initial step in the synthesis process?

• Hydrogenation of trans-2-butene

• Oxidation of trans-2-butene

• Dihalogenation of trans-2-butene

• Elimination reaction of trans-2-butene

What is the role of NaNH2 in the synthesis process?

• To catalyze the hydrogenation reaction.

• To act as a solvent for the reaction.

• To act as a strong base for elimination reactions.

• To stabilize the intermediate compound.

What is the final product of the synthesis process?

• A dibromo compound

• An alkyne

• Trans-2-butene

• Cis-2-butene

Which catalyst is used for the selective hydrogenation of the alkyne?

• Raney nickel

• Platinum oxide

• Palladium on carbon

• Lindlar catalyst

How many elimination reactions are needed to form the alkyne?

• Three

• Two

• Four

• One

What is the purpose of using a strong base in the synthesis?

• To neutralize the reaction mixture

• To act as a catalyst

• To increase the temperature of the reaction

• To facilitate elimination reactions