Please Someone?

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1 Answer
May 22, 2018

A diastereomer is a non-superimposable non-mirror image of a molecule with more than one chirality center.

A simple heuristic I use is: Look for molecules that have at least one chirality center in common and one or more inverted.

I find the method with the highest certainty is using RS configuration. I've noted each's configuration below (the more practice you get, the quicker you will get).

puu.sh

Hence,

#(iii)# and #(iv)# are the same molecule, as well as enantiomers of #(i)#.

#(i)# and #(ii)# are diastereomers. #(1)#