Using CCOC(=O)C(F)(F)F, COc1ccc2c(c1)C(=O)CCC2 to produce COc1ccc2c(c1)C(=O)C(C(=O)C(F)(F)F)CC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.