Q.28. - Organic Chemistry

Question

Question: Draw the aldol product formed from each pair of starting materials using $\mathit{O}\mathit{H}\mathbf{,}\mathbf{ }{\mathit{H}}_{\mathbf{2}}\mathit{O}$.

Step-by-Step Solution

Answer

Answer

Step 1: Aldol reaction

The two carbonyl compounds undergo a reaction in the presence of a base to form a  $\beta$-hydroxy carbonyl $\left(C=O\right)$  compound.

Step 2: Mechanism

The process completes in 3 steps. In the first step, the base abstracts the  $\mathit{\alpha }$-hydrogen from the carbonyl compound(s) to form resonance stabilized enolate(s). 

In the next step, the nucleophilic enolate compound thus formed attacks the electrophilic carbon center of another carbonyl  $\left(C=O\right)$ compound. Thus, a new C-C bond is formed between the carbonyl carbon of one compound and the  -carbon of the other.

In the last step, the alkoxide ion is protonated to form the  -hydroxy carbonyl  $\left(C=O\right)$  compound.

Step 3: Products of the given reactions

The tetravalent black balls must be carbon, the white balls must be representing hydrogen, and the divalent red balls must be representing oxygen. 

a. The product  $\beta$-hydroxy carbonyl $\left(C=O\right)$  compound contains a new C-C bond. The product from the reaction is shown here under.

b. The product  $\beta$-hydroxy carbonyl $\left(C=O\right)$  compound contains a new C-C bond. The product from the reaction is shown here under.