Organic Chemistry Questions- Nucleophiles and Electrophiles- Mechanisms

[Futurewomaninmedicine19]

Hello, I am having trouble with a few problems, I would appreciate your help.
The question asks to identify the sequence of arrow pushing patterns in each of the following mechanisms.
For 8.25 I got nucleophilic attack and proton transfer, however, I also got another proton transfer, nucleophilic attack, followed by another proton transfer... I was wondering why the answers are only one nucleophilic attack and proton transfer.
For 8.26, I only got proton transfer and loss of a leaving group, however, the answers were different. Same goes with 8.27, I understood that there was a carbocation rearrangement, but I did not get proton transfer, and loss of a leaving group... any explanation would be MUCH appreciated!

---

Members don't see this ad.

 

[Daniel Schruth]

Hello, assuming you have sent the screen shots without cutting out any parts of the reaction, the answer key you are using is incorrect. For instance, the screenshot you sent for 8.26 just shows two steps of a reaction, so it doesn't make sense for it's answer to name six steps, when they are only showing you two.

The correct answers for what you have shown are as follows:

For (8.25), Mechanism #1: Step 1: Nucleophilic Attack, Step 2: Proton Transfer; Mechanism #2: Step 1: Proton Transfer, Step 2: Nucleophilic Attack, Step 3: Proton Transfer, Step 4: Proton Transfer, Step 5: Loss of a Leaving Group, Step 6: Proton Transfer

For (8.26), Step 1: Proton Transfer, Step 2: Loss of a Leaving Group (ending with a methyl shift carbocation rearrangement)

For (8.27), Step 1: Nucleophilic Attack (next arrow is just showing resonance)

Hope this helps!