Using COCCl, CC1(C)CCC(C)(C)c2c1cc(C(=O)O)c(O)c2Br to produce COCOc1c(C(=O)O)cc2c(c1Br)C(C)(C)CCC2(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.