Using COc1cc(CO[Si](C)(C)C(C)(C)C)ccc1C=O, CCCCC[Mg]Br to produce CCCCCC(O)c1ccc(CO[Si](C)(C)C(C)(C)C)cc1OC, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.