We introduced a regioselective and atom-economical procedure for the synthesis of 3-substituted indoles by annulation of nitrosoarenes with ethynyl ketones. The reactions were carried out achieving indoles without any catalyst and with excellent regioselectivity. No traces of 2-aroylindole products were detected. Working with 4-nitronitrosobenzene as starting material, the 3-aroyl-N-hydroxy-5-nitroindole products precipitated from the reaction mixtures and were isolated by filtration without any further purification technique. Differently from the corresponding N-hydroxy-3-aryl indoles that, spontaneously in solution, give dehydrodimerization products, the N-hydroxy-3-aroyl indoles are stable and no dimerization compounds were observed.

A direct, regioselective and atom-economical synthesis of 3-aroyl-N-hydroxy-5-nitroindoles by cycloaddition of 4-nitronitrosobenzene with alkynones

Scapinello L.;Maspero A.;Tollari S.;Palmisano G.;Penoni A.
2019-01-01

Abstract

We introduced a regioselective and atom-economical procedure for the synthesis of 3-substituted indoles by annulation of nitrosoarenes with ethynyl ketones. The reactions were carried out achieving indoles without any catalyst and with excellent regioselectivity. No traces of 2-aroylindole products were detected. Working with 4-nitronitrosobenzene as starting material, the 3-aroyl-N-hydroxy-5-nitroindole products precipitated from the reaction mixtures and were isolated by filtration without any further purification technique. Differently from the corresponding N-hydroxy-3-aryl indoles that, spontaneously in solution, give dehydrodimerization products, the N-hydroxy-3-aroyl indoles are stable and no dimerization compounds were observed.
3-aroylindoles; Alkynols; Alkynones; Anilines; Annulation; Chemistry; Cycloaddition; Issue 155; N-hydroxyindoles; Nitrosoarenes
Scapinello, L.; Maspero, A.; Tollari, S.; Palmisano, G.; Nicholas, K. M.; Penoni, A.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2096205
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