[sebmista]

Hi, Could you guys be so kind and explain to me why I got these 3 question on this exam wrong? And if possible could you tell me the correct mechanisms and synthesis so that I can better understand the subject  thanks guys and gals!

[Dan]

Curly arrows should start from a pair of electrons - either a lone pair or a bond. You have several starting from H. For example, protonation of an alcohol, start the arrow from the O: pointing to H⁺, not the other way round.

For Q4, draw out the mercurinium intermediate, and don't assume that water is present. What could happen? The reason you missed this that you have skipped over the mechanism in your first step.

Q7, all you have to do is a add the thiol to the second alkene in exactly the same way as the first. Make sure your curly arrows start from electrons, and watch charges.

Q8, think about carbocation rearrangements. Which carbocation could rearrange to give the desired structure?

[enahs]

If your professor does not post correct exam keys after the test, ask them to do so. It is just silly not to, as it helps so many people.

[tbuihuu]

my opinion