91Ó°ÊÓ

Which of the following bases could be used to deprotonate 1-butyne?

(a)

Which of the following bases could be used to deprotonate 1-butyne?

(c)

How would you prepare cis-2-butene starting from propyne, an alkyl halide, and any other reagents needed? This problem can’t be worked in a single step. You’ll have to carry out more than one reaction.

The following cycloalkyne is too unstable to exist. Explain

The final step in the hydration of an alkyne under acidic conditions is the tautomerization of an enol intermediate to give the corresponding ketone. The mechanism involves a protonation followed by a deprotonation.

Show the mechanism for each of the following tautomerizations.

Give IUPAC names for the following compounds:

Draw structures corresponding to the following names:

(a)3,3-Dimethyl-4-octyne

(b)3-Ethyl-5-methyl-1,6,8-decatriyne

(c)2,2,5,5-Tetramethyl-3-hexyne

(d)3,4-Dimethylcyclodecyne

(e)3,5-Heptadien-1-yne

(f)3-Chloro-4,4-dimethyl-1-nonen-6-yne

(g)3-sec-Butyl-1-heptyne

(h)5-tert-Butyl-2-methyl-3-octyne

Terminal alkynes react with and water to yield bromo ketones. For example:

Propose a mechanism for the reaction. To what reaction of alkenes is

the process analogous?

Propose structures for hydrocarbons that give the following products

on oxidative cleavage by KMnO₄ or O₃ :

Question: Identify the reagents a–c in the following scheme: