Using O=[Cr](=O)([O-])Cl, CCCCC12CCCC=C(C)C1(O)c1ccc(OCOC)cc1C2 to produce CCCCC12CCCC(=O)C(C)=C1c1ccc(OCOC)cc1C2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.