Using C[Mg]Br, CC1(C)O[C@H]2O[C@H]([C@H]3CO3)C[C@H]2O1 to produce CC[C@@H](O)[C@@H]1C[C@H]2OC(C)(C)O[C@H]2O1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.