Predict the products you would expect from the reaction of NaBH₄ with the following compounds. You may assume that these reactions take place in methanol as the solvent.
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Verified step by step guidance

1. Step 1: Identify the functional groups in the given compound. The structure contains an aldehyde group (-CHO) and a lactone (cyclic ester). These are the groups that can potentially react with NaBH4.
2. Step 2: Understand the reactivity of NaBH4. Sodium borohydride (NaBH4) is a reducing agent that selectively reduces aldehydes and ketones to their corresponding alcohols. It does not typically reduce esters under mild conditions.
3. Step 3: Predict the reduction of the aldehyde group. The aldehyde group (-CHO) will be reduced to a primary alcohol (-CH2OH) by NaBH4 in methanol solvent.
4. Step 4: Consider the lactone group. Since NaBH4 does not reduce esters under these conditions, the lactone group will remain unchanged in the product.
5. Step 5: Combine the results. The final product will have the aldehyde group converted to a primary alcohol, while the lactone group remains intact. The structure of the product will reflect these changes.

Key Concepts

Reduction Reactions

Reduction reactions involve the gain of electrons or the decrease in oxidation state by a molecule. In organic chemistry, this often refers to the conversion of carbonyl compounds (like aldehydes and ketones) into alcohols. Sodium borohydride (NaBH4) is a common reducing agent that selectively reduces these functional groups, making it essential to understand its reactivity in predicting products.

Sodium Borohydride (NaBH4)

Sodium borohydride is a mild reducing agent used primarily for the reduction of aldehydes and ketones to their corresponding alcohols. It is less reactive than lithium aluminum hydride, allowing for selective reductions without affecting other functional groups. Understanding its mechanism and selectivity is crucial for predicting the outcome of reactions involving carbonyl compounds.

Solvent Effects in Organic Reactions

The choice of solvent can significantly influence the course of organic reactions. In this case, methanol serves as a polar protic solvent that can stabilize ions and facilitate the reaction between NaBH4 and the carbonyl compound. Recognizing how solvents affect reaction rates, product distributions, and mechanisms is vital for accurate predictions in organic chemistry.