Using C=C(OCC)[Sn](CCCC)(CCCC)CCCC, CC1(C)CC(=O)Nc2ccc(Br)cc21 to produce CC(=O)c1ccc2c(c1)C(C)(C)CC(=O)N2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.