[Jessica09]

I need help with these three problem. I attempted to do them, but I am stumped.
They are attached.

[AlphaScent]

What type of reaction is each reaction?

What is the reactivity of the compounds?

What is the justification for the third mechanism?

[AlphaScent]

If you show some attempt at the first two (forum rules) I would be happy to help you work through the answer.

[Jessica09]

I tried my best, but I couldn`t finish the second one.

Is the third one correct?

[Jessica09]

If you show some attempt at the first two (forum rules) I would be happy to help you work through the answer.

My attempt is above. Thanks for helping me

[Babcock_Hall]

Your reaction involving pyridine looks basically OK, but the reaction might be concerted.  Your instructor may not be concerned with that level of detail, however.  YOur reaction involving acetone has a problem in that near the end, you seem to have lost a methyl group.

[orgopete]

For 1), curved arrows show electron movement. Magnesium(+) doesn't have electrons to donate, nor does it show a bond having formed to it. Although the correct intermediate has resulted, it does so despite the curved arrows.

[AlphaScent]

Babco and orgopete have laid out the important aspects.  To add to orgopete and your understanding, what electrons will add to the carbonyl in the first reaction?

[Jessica09]

Since MgBr do not have electrons to donate I used the bond that connects the cyclohexane and MgBr, but I still don`t know what to do after that.

And I found out where the methyl group was missing.

[orgopete]

Since MgBr do not have electrons to donate I used the bond that connects the cyclohexane and MgBr, but I still don`t know what to do after that.

Since the curved arrow signifies a set of directions, you should simply follow them. I understand the ambiguity of using a bond, but since you know a C-C bond Forman the you know the electrons remain attached to the carbon and not the magnesium. Simply draw that product. At this point, nothing more happens. On to the next step and next reagent.

[spirochete]

In a grignard reaction the likely initial product will be an alkoxide where the negative oxygen is coodinated to magnesium. Then the alkoxide is protonated during the aqueous work up.