Protection for the Carbonyl Group

During a synthetic sequence, a carbonyl group may have to be protected against attack by various reagents. It may be possible to protect a reactive carbonyl group selectively in the presence of a less reactive one. The most useful protective groups are the acyclic and cyclic acetals or ketals, and the acyclic or cyclic thio acetals or ketals. Derivatives of carbonyl compounds that have been used as protective groups in synthetic schemes are described in this chapter. Some of the more important carbonyl protective groups are included in Reactivity Chart 5 (Chapter 10).