The first phase transfer-catalysed direct γ-substitution of Morita-Baylis-Hillman carbonates of isatins with 3-substituted oxindoles has been developed, which affords 3-alkenyl-oxindole ring-fused 3,3'-disubstituted oxindoles in up to 83% yield under mild reaction conditions. Furthermore, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3 and human leukemia cells K562, using MTT-based assays with the commercially available standard drug Cisplatin as a positive control. Gratifyingly, compounds 3aa, 3ba and 3ca exhibited comparable in vitro inhibitory activities against human prostate cancer cells (PC-3) to Cisplatin. What's more, 3ba also had a good inhibition ability against human leukemia cells K562. These results indicate that 3-alkenyl-oxindole ring-fused 3,3'-disubstituted oxindole analogs may be potential lead compounds for further biological screening.

C16H12O3, monoclinic, P21/c (no. 14), a = 10.9636(14) Å, b = 12.1767(12) Å, c = 10.1557(13) Å, β = 116.588(16)°, V = 1212.4(3) Å3, Z = 4, Rgt (F) = 0.0366, wR ref (F 2) = 0.1019, T = 250.00(10) K.