Reactivity of aldehydes and ketones

There are two factors that influence the reactivity of aldehydes and ketones.

1) electronic effects 2) steric effect

We discussed electronic effects thoroughly with respect to the carboxylic acid derivatives. We used data from section 7.9 of the text and were able to explain how electron donating and electron withdrawing groups affected the reactivity of the various carbonyl compounds (just as donors and withdrawers affected the acidity/basicity of substituted benzene derivatives).

Can you see the connection and explain?

In class on March 30, we considered the electronic effects of ketones and aldehydes that determine their relative reactivities compared to other carbonyl derivatives.

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Take a few minutes to explain in your own words the ranking of the carbonyl derivatives. Why are ketones are less reactive than aldehydes?

The second factor to consider is steric effects. As the groups attached to the carbonyl get larger (bulkier), they will hinder the approach of the nucleophile and also destabilize the tetrahedral intermediate that is formed (Figure 2).

In your own words, define what is meant by "sterics."

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Refer to the video below or section 12.2 of the textbook for a summary of the above information!

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