I completely understand where the first reagent comes into play. But for the duels-alder reaction to occur, the single double bond needs to positioned differently and made into two double bonds. So, I figured NBS would add bromide to the cyclopentene and then Bu4N+I- would abstract the proton to displace double bond positioning. First of all it's not strong enough of a base to do that AND it does not lead to an I-Br byproduct. Please help for good karma!