Using C=C(OCC)[Sn](CCCC)(CCCC)CCCC, COC(=O)c1ccnc2c(Br)cccc12 to produce COC(=O)c1ccnc2c(C(C)=O)cccc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.