Total Synthesis of Murrayanine Involving 4,5‐Dimethyleneoxazolidin‐2‐ones and a Palladium(0)‐Catalyzed Diaryl Insertion |
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Authors: | Pablo Bernal Joaquín Tamariz |
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Institution: | 1. Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional. Prol. Carpio y Plan de Ayala, 11340 México, D.F. Mexico, (phone: (+5255)5729‐6300/62411;2. fax: (+5255)5729‐6300/46211) |
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Abstract: | A new total synthesis of the natural carbazole murrayanine ( 1 ) was developed by using the 4,5‐dimethyleneoxazolidin‐2‐one 12 as starting material. The latter underwent a highly regioselective Diels–Alder cycloaddition with acrylaldehyde (=prop‐2‐enal; 13 ) to give adduct 14 (Scheme 3). Conversion of this adduct into diarylamine derivative 9 was carried out via hydrolysis and methylation (Scheme 4). Differing from our previous synthesis, in which such a diarylamine derivative was transformed into 1 by a PdII‐stoichiometric cyclization, this new approach comprised an improved cyclization through a more efficient Pd0‐catalyzed intramolecular diaryl coupling which was applied to 9 , thus obtaining the natural carbazole 1 in a higher overall yield. |
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Keywords: | Murrayanine Carbazoles Oxazolidin‐2‐ones |
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