Nucleophilic addition involves attack by a nucleophile on the electrophilic carbon of the carbonyl group, changing the hybridization of the carbonyl carbon from sp² to sp³. This process forms a tetrahedral alkoxide intermediate that captures a proton to yield the neutral product.
Describe the mechanism of nucleophilic addition reactions in aldehydes and ketones, including the change in hybridization of the carbonyl carbon and the intermediate formed.
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In nucleophilic addition reactions with aldehydes and ketones, the nucleophile attacks the electrophilic carbonyl carbon. The process begins with the nucleophile (Nu⁻) attacking the partially positive carbonyl carbon. This attack leads to the formation of a tetrahedral intermediate, breaking the π bond. The oxygen, initially sp²-hybridized, accepts the nucleophile, resulting in the carbonyl carbon undergoing sp³ hybridization. The intermediate is stabilized by the lone pair on oxygen. Finally, proton transfer or elimination of a leaving group generates the product. This mechanism illustrates the nucleophile’s addition to the carbonyl carbon, allowing the formation of various functional groups in organic synthesis.