Using CCOC(=O)C(=O)CBr, NC(=O)C1(NC(=O)OCc2ccccc2)CC1 to produce CCOC(=O)c1coc(C2(NC(=O)OCc3ccccc3)CC2)n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.