Using CCOC(=O)c1c(-c2cc(C(C)(C)C)c(O)c(C(C)(C)C)c2)c2cc3c(cc2oc1=O)CCC3 to produce O=C(O)c1cc2cc3c(cc2oc1=O)CCC3, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.