Using C=CC[Sn](CCCC)(CCCC)CCCC, COC(=O)c1ccc(Br)c2ccccc12 to produce C=CCc1ccc(C(=O)OC)c2ccccc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.