Classroom Card #1868
Organic Synthesis: When and Why
Students attempt to put a set of molecules in chronological order from earliest reported synthesis to most recent
15 to 30 minutes
Students are shown eight different molecules and asked to rank them 1–8 from earliest reported synthesis (1) to most recent (8). They can work in pairs for this first attempt. Usually ~5 minutes is enough time for them to come up with their rankings, and record them on their supplied worksheet.
Next, the name of each molecule is shown, and the pairs are asked if they want to make any changes to their rankings. Most of the names should be easily recognizable to any sophomore undergraduate (penicillin, morphine, ibuprofen, LSD, etc.). They discuss in pairs for another 3–5 minutes and record any changes on their worksheet.
Then the students discuss their rankings in a small group (6–10 students). They give reasons for why they ranked in the order they did, and try and come up with a consensus ranking for the group. Allow 5–10 minutes for this discussion, and have them record final rankings on their worksheet.
Finally, the correct ranking is announced and the students see how they did. They can calculate how far off each of their rankings were. This is an opportunity for a whole-group discussion on the motivations and limitations that go into synthesizing different molecules!