Using CCCCCCCCC1(CCCCCCCC)c2ccccc2-c2ccc(Br)cc21, O=C=O to produce CCCCCCCCC1(CCCCCCCC)c2ccccc2-c2ccc(C(=O)O)cc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.