Hydration of an Aldehyde or Ketone in Basic Solution

Hydration of an Aldehyde or Ketone in Basic Solution THE OVERALL REACTION  

Step 1 Nucleophilic addition of hydroxide ion to the carbonyl group 

Step 2 Proton transfer from water to the intermediate formed in step 1 

Steric and electronic effects influence the rate of nucleophilic addition to a pro-tonated carbonyl group in much the same way as they do for the case of a neutral one, and protonated aldehydes react faster than protonated ketones. 

With this as background, let us now examine how the principles of nucleophilic addition apply to the characteristic reactions of aldehydes and ketones. We ll begin with the addition of hydrogen cyanide. 

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FIGURE 17.4 The mechanism of hydration of an aldehyde or ketone in basic solution. Hydroxide ion is a catalyst it is consumed in the first step, and regenerated in the second. 

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