Using O=Cc1ccc2c(c1)OCO2, CC(=O)c1ccc2c(c1)OCO2 to produce O=C(C=Cc1ccc2c(c1)OCO2)c1ccc2c(c1)OCO2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.