Using COC(=O)c1ccc2ccn(C(=O)OC(C)(C)C)c2c1, C[Sn](C)(C)Cl to produce COC(=O)c1ccc2cc([Sn](C)(C)C)n(C(=O)OC(C)(C)C)c2c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.