Using Br[Mg]c1ccccc1, C[SiH](C)OC1CCCC(C(C)(C)C)CCCCC1=O to produce C[SiH](C)OC1CCCC(C(C)(C)C)CCCCC1(O)c1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.