Using COc1cc(-c2coc3c(C)c(OC(C)=O)ccc3c2=O)ccc1OC(C)=O to produce COc1cc(C2COc3c(ccc(OC(C)=O)c3C)C2O)ccc1OC(C)=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.