Woman finally changes sides, finding compound (5)
I believe the answer is:
ether
'compound' is the definition.
(chemical compound)
'woman finally changes sides' is the wordplay.
'woman' becomes 'her' (pronoun for a woman).
'finally' is a charade indicator (letters next to each other).
'changes sides' becomes 'et' (I am not sure about this - if you are sure you should believe this answer much more).
'her' after 'et' is 'ETHER'.
'finding' is the link.
(Other definitions for ether that I've seen before include "Chemical solvent" , "Volatile organic liquid once used as a general anaesthetic" , "There goes the anaesthetic" , "Gas - air - space" , "Clear upper air" .)