An efficient catalytic cyclization of β‐nitrostyrenes to indoles was developed. The reaction was applied to the synthesis of 3‐arylindoles and 2‐alkylindoles. Given that in the latter case the starting β‐nitrostyrenes can be easily obtained by a Henry reaction, the present method allows indoles to be obtained in a two‐step sequence starting from cheap reactants.

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Synthesis of Indoles by Palladium-Catalyzed Reductive Cyclization of -Nitrostyrenes with Carbon Monoxide as the Reductant. -The optimized conditions are applied to the preparation of a series of 2-or 3-substituted indole structures bearing additional functions at the arene part. The transformation of the unsubstituted substrate (IX) leads mainly to polymerization. Mixtures of regioisomers are identified for educts (XI) and (XIV). -(FERRETTI, F.; EL-ATAWY, M. A.; MUTO, S.; HAGAR, M.; GALLO, E.; RAGAINI*, F.; Eur. J. Org. Chem. 2015, 26, 5712-5715, http://dx.doi.org/10.1002/ejoc.201500933 ; Dip. Chim., Univ. Studi, I-20133 Milano, Italy; Eng.) -Lehmann 03-111