The commonly used lithiating reagent, BuLi can be used for the thiophene-derivatives having primary amine; e.g. 4-(thiophen-2-yl)aniline. Alternatively which reagents can be used to get the lithiated product without interfering the -NH2.
Without PG on aniline I will say it is unlikely to get what you want and it is not a question of lithiation reaction. pKa of aniline (NH2 group) is around 30 (D.H. Ripin, D.A. Evans). And it is of the same magnitude that of alpha position of thiophen pKa=33. (Baran, Richter) As I understand that is a target position that you want to lithiate. So acording to pKa whatever you will use you will first take proton from aniline and only then from thiophen. I believe that procedure you refer to is dialing with alkyl-amines primary or secondary dose not matter, there pKa are much higher 37-44, what allowed you to do selective thiophen lithiation.
The NH2 group is vastly more acidic than any of the CH protons, so you can't selectively lithiate anything but the nitrogen.
You could probably add a second equivalent of n-BuLi (or t-BuLi) and lithiate the aromatic ring, but the NHLi might interfere with whatever you have in mind next. If that's the case, you'll have to protect the aniline.
Another option is to prepare the substrate with a bromine or iodine in your desired location for lithiation. It's possible to transmetalate ArI or ArBr at low temperature, even in the presence of the NH2 group, but your next reaction will have to be a fast one.
I think making the dianion is your better bet; Use two equivalents of t-BuLi , stir at -40° C for 1hr before rapid addition of a single equivalent of your electrophile in THF. Run the reaction fairly dilute in THF, as the hexanes that t-BuLi invariably comes in can be quite disruptive to dianion solubility.
The strong electronic communication between the desired thiophene position and the aniline functionality may make dianion formation quite difficult.
Transmetallation works well for iodides and bromides but it is unlikely that any reaction you do with the resulting anion is faster than proton transfer from the electronegative nitrogen atom of the aniline; which is both kinetically and thermodynamically favourable.
In terms of a good protecting group I would recommend using 1,2-bis(chlorodimethylsilyl)ethane, known as stabase. Which is stable to n-BuLi
LDA can be used alternatively; further the protection of -NH2 by acetyl group and use of LDA may ensure the clean lithiation on thiophene.
I have doubts that LDA would give you the dianion due to electronic communication through the aromatic ring, removing the second proton would be considerably more difficult.
Using an acetyl group introduces two problems, the additionally acidic methyl group and also the possibility of directed ortholithiation which is a particular problem for protecting anilines in the presence of strong bases.
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