Question

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

Short answer

Answer

a.

b.

c.

Step-by-step solution

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

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