When looking over an old organic midterm I came across this question.
As you can see I got half of it right, but honestly I'm not sure how I got that one right or how you would answer this in general. Looking back at this now it appears that the first signal was split into a doublet and each peak was then split into a triplet, which makes sense for proton
c (first split by
b and then by
The second one seems trickier. It looks as though the signal was split into a quartet, and then each peak into a triplet. To me that looks like it should be
d - split into the quartet by
e and then split into the triplets by
b. So why is the answer
b? These J values wouldn't have been supplied for now reason - is there a way I could have used them? More generally, is it possible (and if so how) to identify the type of proton and the structure of a molecule if you just had access to the NMR and the J values like this?