This is a concept that probably is largely out of favor. In the olden days, students were asked to propose routes from air, fire, and water. Well, not quite that far back, but the question is seemingly asking how all the various chemicals are obtained. This can come down to understanding the various commercial processes. The regiochemistry of a reaction is often found in the price of the chemical, or you can think in the opposite direction knowing the price, what was the route of synthesis.
Catalog prices have different influences. You can begin to learn how something is made if you think about ordering a tank car of something. Who are the suppliers and how do they make it. You won't find that in a speciality catalog. You will find commercial production can have a great influence on price and may provide the incentive for a new and chemically superior routes. Similarly, there may be precedent for superior routes that is not being utilized because of a lack of demand. If someone wanted something, the price may change greatly.