Using COC(=O)C(CC12CCC(c3ccc(Br)cc3)(CC1)O2)C(=O)OC to produce COC(=O)CCC12CCC(c3ccc(Br)cc3)(CC1)O2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.