Using O=C(O)[C@@H](O)[C@@H](CC1CCCC1)C(=O)O, COC(C)(C)OC to produce CC1(C)OC(=O)[C@H]([C@@H](CC2CCCC2)C(=O)O)O1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.