Retrosynthesis Analysis with examples & evidence

Retrosynthesis analysis is a technique that helps organic chemists design the synthesis of complex molecules from simpler ones. It involves working backwards from the target molecule and breaking it down into simpler fragments that can be obtained from known reactions. Retrosynthesis analysis can help find multiple possible routes to synthesize a molecule and compare their advantages and disadvantages in terms of cost, efficiency, environmental impact, and stereochemical control.


Here are some examples of retrosynthesis analysis with evidence from web search results:

The target molecule is an ether, which can be formed by an S N 2 reaction between a halide and a methoxide ion. The halide can be obtained by a radical halogenation of toluene. The retrosynthesis analysis can be shown as follows:

! [retrosynthesis example 1]

The forward synthesis can be written as:

! [synthesis example 1]

The target molecule is an alcohol, which can be formed by a hydroboration-oxidation of an alkene. The alkene can be obtained by an elimination reaction of an alkyl halide. The alkyl halide can be obtained by an alkylation of ethyl bromide. The retrosynthesis analysis can be shown as follows:

! [retrosynthesis example 2]

The forward synthesis can be written as:

! [synthesis example 2]

I hope this helps you understand more about retrosynthesis analysis and its applications in organic chemistry. If you want to learn more about this topic, you can visit some of these links:



More Critical Thinking about Retrosynthesis Analysis:

Retrosynthesis analysis is not only a useful technique for organic chemists, but also a creative process that involves imagination, logic, and problem-solving. Retrosynthesis analysis can be seen as a puzzle game, where the goal is to find the simplest and most elegant way to assemble the pieces of a complex molecule. Retrosynthesis analysis can also be compared to a journey, where the destination is the target molecule, and the route is the sequence of reactions. Retrosynthesis analysis can inspire curiosity, challenge, and satisfaction for those who practice it.
To illustrate the creative aspect of retrosynthesis analysis, I have composed a poem based on the example of synthesizing 2-methyl-2-pentanol from ethyl bromide:
A molecule of beauty and complexity
Is what I want to make with chemistry
But how can I achieve this lofty goal
With only simple reagents in my bowl?

I start by looking at the final product
And think of ways to break it down and cut
I see an alcohol with five carbons long
And wonder what reactions can go wrong

I know that alcohols can come from alkenes
By adding water with borane machines
But how can I obtain the right alkene
With the right position and geometry?

I recall that alkenes can come from halides
By losing HX with strong base guides
But how can I obtain the right halide
With the right carbon chain and branching side?

I remember that halides can come from alkanes
By adding RX with light or heat flames
But how can I obtain the right alkane
With the right number of carbons in its frame?

I realize that alkanes can come from bromides
By coupling RBr with sodium hydrides
But how can I obtain the right bromide
With the right alkyl group to match its stride?

I find that bromides can come from ethane.
By replacing HBr with ethyl's name
But how can I obtain ethane so plain?
With only two carbons and no other stain?

I finally see that ethane is my source.
The simplest compound that I can endorse.
From ethane I can build my molecule
By following the steps of retrosynthesis rule

I have solved the puzzle of synthesis.
By working backwards from analysis
I have enjoyed the journey of creation.
By using my imagination and logic combination

Retrosynthesis is more than just a skill.
It is also an art that gives me thrill.

                                                              BY ALEENA SAEED 

                                                            University of Chakwal

                                                          Department of Chemistry

   aleenasaeed773@gmail.com