Synthesis of 1-cyclopentylpropan-1-amine from cyclopentene

[Joshua Law]

Hello there!

Can anyone please tell me how to theoretically synthetize 1-cyclopentylpropan-1-amine from cyclopentene in exactly 6 steps (no more, no less steps)?

Thank you for all your answers!

[hypervalent_iodine]

Is this a homework question? Could you possibly share your own thoughts on where to start? 

[Joshua Law]

I started with Friedel-Crafts reaction using propanoyl chloride and AlCl3, with cyclopentylpropane-1-one as a product of the first step. Then I thought about reduction of the ketone using NaBH4 and MeOH resulting into 1-cyclopentylpropane-1-ol (that's the second step). As the third step using TsCl and pyridine to create (1-chloropropyl)cyclopentane.

The problem is that everything that comes to my mind uses only 5 steps, not 6 I need.

[hypervalent_iodine]

You might want to rethink that first one and maybe have a look at what substrates you would generally perform FC reactions on. Could you draw a scheme out?

[Joshua Law]

I got an idea about a whole different way of constructing this synthesis.

Do you think this way is possible?

Thanks a lot! 

[hypervalent_iodine]

By which you mean someone from another forum gave you the answer. Not exactly helpful as far as you learning how to do it yourself is concerned, but sure, looks fine.

Did you happen to figure out why FC was a bad choice in your first attempt?

[Joshua Law]

Yes, you're right.

I was trying to figure it out for few hours and no idea that used exactly 6 steps didn't come to my mind, only with 2 or 5. I needed badly to finish this synthesis, so I asked here and there hoping for someone solving this task. Didn't mean to present someone's work as mine, but I didn't think it was important to mention it. 

That's it.

Thanks.

Edited August 21, 2019 by Joshua Law

[hypervalent_iodine]

25 minutes ago, Joshua Law said:

Yes, you're right.

I was trying to figure it out for few hours and no idea that used exactly 6 steps didn't come to my mind, only with 2 or 5. I needed badly to finish this synthesis, so I asked here and there hoping for someone solving this task. Didn't mean to present someone's work as mine, but I didn't think it was important to mention it. 

That's it.

Thanks.

But your first attempt with 5 steps was wrong, and you still haven’t really shown that you understand why. That’s why it’s important. The person from the other forum won’t be in your exams to do them for you, so you need to understand how to get to the solution by yourself.

[BabcockHall]

It is also important to give credit where credit is due under any circumstance.

[Joshua Law]

Credits to user "rolnor" who helped me with the synthesis on the other forum.

And I see now, I was stupid, Friedel-Crafts can be used only with aromatic ring, right? That's the one important detail I forget...