Using C=C(OCC)[Sn](CCCC)(CCCC)CCCC, CCOC(=O)/C=C/c1ccc(OCc2ccccc2)cc1Br to produce CCOC(=O)/C=C/c1ccc(OCc2ccccc2)cc1C(C)=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.