[phth]

I understand that 1-iodo-hexane reducing with LiAlH₄ proceeds through a SET pathway; RMgBr proceeds like this too.  Specifically LiAlH₄: are the mechanisms of LiAlH₄ reductions in undergrad textbooks a simplification? If not are there substrates (e.g. aldehyde, carboxylic acid,) where the double electron G^≠ becomes lower?