Using O=Cc1[nH]cc2c1OCCO2, CC(C)(C)OC(=O)OC(=O)OC(C)(C)C to produce CC(C)(C)OC(=O)n1cc2c(c1C=O)OCCO2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.