Retrosynthetic analysis is the method of working backwards from a target compound to starting materials.
To write a synthesis working backwards, an open arrow is used to indicate that the product is drawn on the left and the starting material on the right.
In designing a synthesis, reactions are often divided into two categories:
1. Those that form new carbon-carbon bonds.
2. Those that convert one functional group into another, that is, Functional Group Interconversions (FGI).
