Metalation of thiophene

So lately I've been studying the concerted metalation-deprotonation of thiophene and I came to the conclusion that the alpha positions of thiophene are the most reactive, which is why one of those alpha carbons (either at the 2 or 5 position) will be deprotonated en metalated.


But why are the alpha carbons on thiophene the most reactive ones and why is thiophene preferred during concerted metalation-deprotonation if there are other heterocyclic compounds that are more reactive?


Thanks!


