Earlier quoted context omitted.
A friend of mine once asked his TA about (my memory fails here) either how to activate a leaving group or set up a protecting group at a given hypothetical structure. The TA, without batting an eyelid, responded "I think you'll find all the precursors are scheduled, too." The next lab, the TA, presumably having reflected a bit and in the middle of an unrelated discourse, added "remember, always characterise any synth…
What is a group ? (Group of people, or some chemical compound, or some kind of corporate structure, protecting possibly illegal stuff going on in one of the groups?) Are all the precursors scheduled, or is the punchline that the TA was wrong? Why would one do well to remember to characterise any synthesis undertaken? To protect oneself against legal action by showing that the labs purpose was synthesising legal compo…
https://en.m.wikipedia.org/wiki/Leaving_group
You design your synthesis around this and try to pick pathways that are easy, have the highest yields, and don't produce undesirable products you have to remove.