Q.46. - Organic Chemistry

Question

Question: What starting materials are needed to synthesize each compound using a Robinson annulation?

Step-by-Step Solution

Answer

Answer

 

a.

b. 

c.

Step 1: The Robinson annulation

 The Robinson annulation involves the formation of a six membered cyclic ring from an  $\mathit{\alpha }\mathbf{,}\mathit{\beta }$-unsaturated ketone and an enolate forming carbonyl compound. The steps in Robinson Annulation involve Michael addition followed by Aldol condensation.

An example is shown below:

Example of Robinson Annulation

Step 2: Retrosynthetic analysis

a.

The retrosynthetic breakdown of the target molecule gives the following starting materials:

Starting materials of a

 

b.

The following starting materials are obtained upon retrosynthetic analysis:

Starting materials of b

 

c.

The following started materials undergo Robinson annulation to give the given product:

Starting materials of c