Substrate-directed divergent synthesis of fused indole polycycles through Rh(ii)-catalyzed cascade reactions of bis(diazo)indolin-2-ones

Herein, we report a substrate-directed diverse synthetic strategy toward two kinds of structurally intriguing fused indole polycycles through Rh(ii)-catalyzed cascade reactions of bis(diazo)indolin-2-ones with enaminones. The subtle structural changes in enaminones lead to different reactivities. Cyclic enaminones produce indolo[2,3-b]indoles, whereas acyclic ones afford oxazolo[3,2-a]indoles.

Automated summary

In this study, a substrate-directed diverse synthetic strategy was reported for the synthesis of two kinds of structurally intriguing fused indole polycycles through Rh(ii)-catalyzed cascade reactions. The subtle structural changes in enaminones result in different reactivities.