What are protecting groups in organic synthesis?
A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis.
Why protecting group is used in organic synthesis?
Protecting groups are used in synthesis to temporarily mask the characteristic chemistry of a functional group because it interferes with another reaction. A good protecting group should be easy to put on, easy to remove and in high yielding reactions, and inert to the conditions of the reaction required.
Which is the protecting group for alcohol?
The most common protecting groups for alcohols are the silyl ethers. Here is the idea behind it. We take a silyl chloride, do a substitution using the alcohol as a nucleophile and then the alcohol converted into a silyl ether can be used in the presence of any strong base including the Grignard reagent.
How do you protect a carbonyl?
Therefore, methods are developed for the protection of carbonyl compounds and various protective groups can be used [1]. Acetal, 1-3-dioxalane, mixed ketal and thioketal are the widely used protective groups. Aldehydes and ketones are the most common groups that are protected by these methods.
What is an acetal protecting group?
Acetals are commonly used to protect the carbonyl groups of aldehydes and ketones from basic, nucleophilic reagents. Once the protection is no longer needed, the acetal protect- ing group is easily removed, and the carbonyl group re-exposed, by treatment with dilute aqueous acid.
Why protecting group is necessary in synthesis of a peptide explain with a suitable example?
Peptides are chemically synthesized by the condensation reaction of the carboxyl group of one amino acid to the amino group of another. Protecting group strategies are usually necessary to prevent undesirable side reactions with the various amino acid side chains.
Which protecting group is used for the formation of carbonyl?
Cyclic acetals
Cyclic acetals and ketals are the most useful carbonyl (aldehyde or ketone) protecting groups. Common diols used to form ketals are show below in order of their relative rate of formation. 1,3-dioxanes cleave faster than 1,3-dioxolanes. Acetals and ketals are easily formed and cleaved.