Acetal Formation: Acid‑Catalyzed Carbonyl Protection

Learn acetal formation step-by-step: acid-catalyzed addition of alcohol to carbonyls, hemiacetal intermediates, and dehydration to acetals. Includes when/why to use acetals as protecting groups.

• Overall transformation: Aldehyde/ketone → acetal (with ROH, acid)
• Key intermediate: Hemiacetal
• Driving strategy: Use excess alcohol and remove water to push equilibrium
• Protecting-group logic: Acetals protect carbonyls from nucleophiles/bases; deprotect in acid + water
• Exam type: Choose conditions
• Exam type: Predict the major product
• Exam type: Synthesis / retrosynthesis