Construction of Hydrodibenzo[,]furan Frameworks from Morita-Baylis-Hillman Carbonates of Isatins and -Hydroxy Enones via Palladium and Brønsted Base Relay Catalysis.

A cascade assembly between isatin-derived Morita-Baylis-Hillman carbonates and -hydroxybenzylideneacetones has been developed under the relay catalysis of Pd(PPh) and DBU, affording a spectrum of 1,2,3,4-tetrahydrodibenzo[,]furan architectures incorporating a spirooxindole motif in moderate to good yields with excellent diastereoselectivity. The fused indole analogues were similarly furnished by employing the benzylideneacetones having an -TsNH group.