[Anna26]

Hello everybody. I have an exam soon concerning retrosynthesis, but I don't know how to think when dealing with such exercises!!! Please help

[Guitarmaniac86]

The subject of retrosynthesis is so vast and your question is so vague, that the only way to possibly help you would be to write a textbook.

I have you covered.

For basics of retrosynthesis, read chapter 30 pages 771 - 801 in Clayden, or search the appendix at the back  for the chapter in whatever edition you find.

Also, why not post a simple retrosynthesis with your attempts and I or others can walk you through the question, but you have to show an attempt first.

[Anna26]

Thank you Guitarmaniac86.

How can I solve this problem for example?

[Anna26]

[Guitarmaniac86]

Is that an aldehyde or a carboxylic acid?

If its a carboxylic acid: http://www.masterorganicchemistry.com/2011/05/20/common-mistakes-with-carbonyls-carboxylic-acids-are-acids/

If its an aldehyde: http://www.masterorganicchemistry.com/2016/01/13/synthesis-using-grignard-reagents-1/

[kriggy]

This is not realy an example of retrosynthesis but you to be able to do retrosynthetic analysis you need to have some knowledge of reactions, without that is impossible

[Vidya]

Thank you Guitarmaniac86.

How can I solve this problem for example?

You have posted a reaction ...
Retrosynthesis is get the starting materials step by step from the final product ... means going from the target molecule to simple starting precursers.