The Reactions of Aldehydes and Ketones with Cyanide Ion

Show how the following cort5)ounds could be synthesized from cyclohexanol. 

5 THE REACTIONS OF CARBONYL COMPOUNDS WITH ACETYLIDE IONS 

We have seen that a terminal alkyne can be converted into an acetylide ion by a strong base (Section 7.11). 

An acetylide ion is another example of a carbon nucleophile that reacts with an aldehyde or a ketone to form a nucleophilic addition product. When the reaction is over, a weak acid (one that will not react with the triple bond, such as the pyridinium ion shown here) is added to the reaction mixture to protonate the alkoxide ion. 

Show how the following compounds can be prepared, using ethyne as one of the starting materials. Explain why ethyne should be alkylated before, rather than after, nucleophilic addition, a. l-pentyn-3-ol b. l-phenyl-2-butyn-l-ol c. 2-methyl-3-hexyn-2-ol  

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