Using O=C1CCOCC1, COc1cc(C=O)cc(OC)c1OC to produce COc1cc(C=C2COCC(=Cc3cc(OC)c(OC)c(OC)c3)C2=O)cc(OC)c1OC, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.