Synthesis of indole derivatives by domino hydroformylation/indolization of 2-nitrocinnamaldehydes

The present work furnishes an innovative preparation of substituted indoles based on tandem hydroformylation, where the chemo- and the regio-selectivities are good, so the yield of the reaction. The novelty has been established in the four-step transformation of substituted alpha nitrocinnamaldehydes into desired indoles in a one-pot reaction. Under hydroformylation reaction conditions we have been able to trigger off a cascade of reactions, which gave substituted indoles in high yields. Useful intermediates are prepared by using this technique for the synthesis of well-known biologically active molecules.

Graphical abstractIntermediates of biologically active 3,5-substituted indole derivatives have been successfully obtained by rhodium-catalyzed domino hydroformylation/indolization of m-substituted-o-nitrocinnamaldehyde diethyl acetals.Figure optionsDownload full-size imageDownload as PowerPoint slide