Using COc1ccc2c(c1)CC1(CCOS(C)(=O)=O)CCC(=O)C(C)=C21, [I-] to produce COc1ccc2c(c1)CC1(CCI)CCC(=O)C(C)=C21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.