[Nescafe]

Hello,

I was reading about Click v.s. 1,3 cycloaddition and am having a hard time figuring out why Cu catalyzed click is not a 1,3 cycloaddition. Also, I find that the click mechanism is still under debate, does anyone know a single mechanism that is the least contested?

Thanks in advance,

Nescafe.

[408]

1,3-is concerted, ie, both sides go at same time.

Get a transition metal in there, you are going to have stuff coordinating.  Both sides can't go if one is coordinated. 

[Nescafe]

1,3-is concerted, ie, both sides go at same time.

Get a transition metal in there, you are going to have stuff coordinating.  Both sides can't go if one is coordinated.

That makes sense, thanks for that, here is a snack! =)

Thanks,

Nescafe.

[Nescafe]

1,3-is concerted, ie, both sides go at same time.

Get a transition metal in there, you are going to have stuff coordinating.  Both sides can't go if one is coordinated.

How would one find out whether it is a concerted mechanism or not? Would it be required to do kinetic experiments as well as 14C or 15N labelled material to confirm a hypothesis? What is the typical way of determining it?

Thanks again,

Nescafe.

[TheUnassuming]

I've seen examples of people doing kinetic studies by NMR, trying to trap one of the intermediates, or quenching and work up the reaction before its complete and characterize the biproducts. 
If you can pull it off NMR would probably be the easiest. 

[kriggy]

How would one find out whether it is a concerted mechanism or not? Would it be required to do kinetic experiments as well as 14C or 15N labelled material to confirm a hypothesis? What is the typical way of determining it?

Thanks again,

Nescafe.

Depends how fast is the reaction. If its slow enough you can isolate the intermediate or do HPLC-MS  if not maybe stopped flow methods should work.
what reaction are you talking exactly? Can you share article or link?