[xshadow]

Hi

According to us which reaction will occour with  2-chloro tiophene + BuLi ??!!

A)  ortho -lithiation on the other free ortho position
B) metal halide echange 

I read that  metal echange reaction are very fast...but also with chloride? (have to break the C-Cl bond, stronger than the C-Br/C-I)

THANKS

[rolnor]

I dont know, I guess you gett lithiation in the 5-position. Can you use Scifinder or Reaxys? If you want to be sure you can use LDA to get pure 5-metalation. If you want metalation in the 2-position you can use magnesium and make a Grignard. Its possible you need to use excess magnesium+1,2-dichloroethane to get good Grignard.

[xshadow]

I dont know, I guess you gett lithiation in the 5-position. Can you use Scifinder or Reaxys? If you want to be sure you can use LDA to get pure 5-metalation. If you want metalation in the 2-position you can use magnesium and make a Grignard. Its possible you need to use excess magnesium+1,2-dichloroethane to get good Grignard.

Thanks.
No i can't

So is LDA  better than BuLi in tiophene orto lithiation?

[rolnor]

You dont get halogen-metal exchange with LDA, you only pick the acidic 5-proton.

[xshadow]

You dont get halogen-metal exchange with LDA, you only pick the acidic 5-proton.

Thanks!!