it's my first post so please forgive possible redundant questions or not up to quenstion-standard phrasings.
I have a question about a reaction I've been struggling with the last two weeks.
I am trying to alkylate a 3-bromothienothiophene with either a n-C11 chain or oligo ethyleneglycol chain, by means of a first conversion of the chain to a Grignard reagent (successful) and subsequent Kumada coupling with the mentioned aryl bromide.
The problem I experienced is that either no reaction at all occurs (even after reflux in THF for 30 hours I only isolated the unreacted aryl-bromide). In case of C11 chain, I got a little of the desired product, however in very low yields (below 10 %). However, the Grignard chain seems to be consumed, probably by homocoupling with itself.
My question is if you have pro-tips for Kumada coupling reactions, or also if maybe the thienothiophene is too electronrich for this reaction type. In this case, can you suggest alternative reaction pathways?