Question

Why are allenes important in Organic Chemistry?

What is a Mannich Type Reaction? Please show an example of this.

Answer 1

Allenes are important in Organic Chemistry because:

- Allenes undergo many of the usual double-bond reactions, being readily hydrogenated, adding bromine, and being oxidized with potassium permanganate solution.

-The hydration of allenes resembles the hydration of alkynes in giving initially an unstable enol that rapidly rearranges to a ketone.

Mannich Reaction: The Mannich reaction is an organic reaction which consists of an amino alkylation of an acidic proton placed next to a carbonyl functional group by formaldehyde and a primary or secondary amine or ammonia. The final product is a ?-amino-carbonyl compound also known as a Mannich base.Reactions between aldimines and ?-methylene carbonyls are also considered Mannich reactions because these imines form between amines and aldehydes.

The reaction is named after chemist Carl Mannich.

For example :