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Question
Acetone, Acetaldehyde, Benzaldehyde, Acetophenone – reactivity towards addition of HCN.
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Solution
Acetone, acetaldehyde, benzaldehyde, acetophenone - Reactivity with HCN
\[\begin{array}{c}\ce{CH3-C-CH3}\\\ce{||}\\\ce{O}\end{array}
\begin{array}{c}\ce{CH3-CHO}\\\ce{||}\\\ce{O}\end{array}\ce{C6H5CHO}\begin{array}{c}\ce{CH3-C-C6H5}\\\ce{||}\\\ce{O}\end{array}\]
Nucelophile addition by HCN is strongest for aldehyde than ketones. Also, acetophenone is more sterically hindered than acetone, hence comparatively less nucleophilic similarly C6 H5CHO i -s less reactive towards nucleophilic addition than CH3CHO.
\[\begin{array}{c}\ce{CH3-C-C6H5}\\\ce{||}\\\ce{O}\end{array}
\begin{array}{c}\ce{< CH3-C -CH3}\\\ce{||}\\\ce{O}\end{array}\ce{<C6H5CHO < CH3CHO}\]
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\phantom{....}||\\
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| (i) |  |
| (ii) |  |
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