I know you can add the Mg/ether to a bromo-benzene group and add that to an aldehyde/ketone. Could you substitute a bromo-cyclopentane for the bromo-benzene and have it work in the same way? I don't see why it wouldn't, but I want to be sure. I need to add a cyclopentane to an aldehyde and this seems like a simple way to do it, but little worried I'm missing something here.