Aldehyde + ethylene glycol forms which protecting group?

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Aldehyde + ethylene glycol forms which protecting group?

The protecting group formed is an acetal. When an aldehyde reacts with ethylene glycol in the presence of an acid catalyst, it forms a five‑membered cyclic acetal (1,3‑dioxolane), commonly called the ethylene glycol acetal. This protects the aldehyde by converting the carbonyl into two ether linkages, which are stable under many reaction conditions and can be reversed later by acid hydrolysis to restore the aldehyde. An imine would require an amine, not a diol; a hydrate would be a geminal diol formed by water addition and isn’t used as a protecting group here; a ketal refers to protection of a ketone, not an aldehyde.

The protecting group formed is an acetal. When an aldehyde reacts with ethylene glycol in the presence of an acid catalyst, it forms a five‑membered cyclic acetal (1,3‑dioxolane), commonly called the ethylene glycol acetal. This protects the aldehyde by converting the carbonyl into two ether linkages, which are stable under many reaction conditions and can be reversed later by acid hydrolysis to restore the aldehyde. An imine would require an amine, not a diol; a hydrate would be a geminal diol formed by water addition and isn’t used as a protecting group here; a ketal refers to protection of a ketone, not an aldehyde.

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