Spirocyclic indolone polyethylene glycol carbonate compound, composition, preparation method and use thereof

A spirocyclic indolone polyethylene glycol carbonate compound represented by the following general formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof:

• wherein
• Y1, Y2, Y3, and Y4 are independently selected from the group consisting of H and halogen;
• R1 is selected from the group consisting of H and C1-C5 alkyl;
• R2 is selected from the group consisting of H, C1-C5 alkyl, and C1-C5 alkoxy;
• R3 is selected from the group consisting of C1-C10 alkyl and C2-C10 alkenyl;
• and
• n is an integral of 1 to 80.