Question: what is the major difference between a cyclic hemiacetal and a cyclic acetal?
Answer: Truong-Son N. A cyclic acetal is a protecting group. ... A cyclic hemiacetal is formed when you protonate an aldehyde that has a hydroxyl group far enough away that an intramolecular ring formation can be made, but with only one nucleophilic attack on the same carbonyl carbon, not two.