O=C(O)C1=C[C@@H](O)[C@@H](O)[C@H](O)C1
I did not do docking but just observed the active site of SARS-CoV-2Mpro key residues such as His41, His164 and Cys145. I think this compound may best interact with these residues. Reference: L. Zhang et al., Science 10.1126/science.abb3405 (2020).