Using O=C(O)c1cc2c3c4c(ccc3c1)CC(C(=O)O)CC4C=C2 to produce O=C(O)c1cc2c3c(c1)CCc1cc(C(=O)O)cc(c1-3)CC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.