Which reagent would most likely be used for the oxidation of primary alcohols to aldehydes?

The oxidation of primary alcohols to aldehydes can be effectively achieved using pyridinium chlorochromate (PCC). This reagent is specifically designed to facilitate the selective oxidation of alcohols without further oxidation of the intermediate aldehydes to carboxylic acids.

PCC is a mild oxidizing agent that allows for the conversion of primary alcohols to aldehydes under controlled conditions. It achieves this by forming a chromate ester with the alcohol, which subsequently decomposes to yield the aldehyde. Importantly, the use of PCC minimizes over-oxidation, thus preserving the aldehyde functionality that could otherwise be converted to carboxylic acids with stronger oxidizers.

In contrast, potassium permanganate is a strong oxidizing agent that can oxidize alcohols to carboxylic acids rather than stopping at the aldehyde stage. Sodium borohydride, on the other hand, is a reducing agent rather than an oxidizing agent, making it suitable for the reduction of carbonyl compounds, but it does not serve for oxidation. Hydrochloric acid does not function as an oxidizing agent for this transformation and is primarily used in acid-base reactions.

Thus, the use of pyridinium chlorochromate is