![]() ![]() It’s a lot harder to mess things up if you number your carbons, and redraw your first example EXACTLY as before, only breaking/forming the bonds the arrows tell you to. If you just do everything the arrows tell you to do, draw it ugly, THEN redraw, you will be just fine.Īnother example which trips people up is in doing rearrangements of carbocations. Even when people get this right, I’ve seen them do crazy things like re-draw the carbon still attached to the boron. ![]() The tricky step in the hydroboration mechanism is showing the formation of the carbon-oxygen bond. THEN, once you have the ugly version, take your time to redraw the molecule carefully – one atom at a time. Now, using the arrow formalism rules, form and break all the bonds the arrows tell you to – without moving any atoms around. THEN draw the pretty version.ĭraw in the curved arrows (making sure the carbons are numbered). There are also worries, especially on exams, that you’ll have grades deducted if you draw something that looks gawd-awful. It’s common to want to draw a product that looks pretty, because that’s how it’s drawn in the textbook. ![]() The second most important thing is a bit more subtle. This alone will help you prevent a lot of commonplace errors. The first important thing to make sure you do is to number your carbons. It should be as boring and repeatable as a conversion after a touchdown.įortunately these errors are completely preventable. Drawing the product afterwards is almost purely mechanical. Figuring out where the electrons go is the *hard part*! That’s the part that takes thought. Once you have the arrows drawn right, there is really no reason why you should not end up drawing the product correctly. I see a lot of smart students mess up step 2, even when they draw the right arrows. This is a minor tragedy, by the way. It should be closer to 98/2, not 70/30. I’d say at least 70-80% of the difficulty students have in organic chemistry mechanisms comes from part 1. When figuring out what the product of a reaction is, there are really two important steps. ![]()
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