Using O=C1OC(=O)c2c(Br)c(Br)c(Br)c(Br)c21, Sc1ccccc1 to produce O=C1OC(=O)c2c(Br)c(Sc3ccccc3)c(Sc3ccccc3)c(Br)c21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.