Synthesis of spiro-tetrahydrothiopyran-oxindoles by Michael-aldol cascade reactions: discovery of potential P53-MDM2 inhibitors with good antitumor activity

Using proline as the catalyst, an organocatalytic Michael-aldol cascade reaction was developed for the synthesis of spiro-tetrahydrothiopyran oxindoles. The highly functionalized scaffold was assembled in moderate to good yields (51-78%) and excellent diastereoselectivities (>20:1 dr). Interestingly, the oxindoles displayed moderate to good in vitro antitumor activities and were validated as p53-MDM2 inhibitors, which represented promising lead compounds for antitumor drug discovery.