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Total Synthesis of Murrayanine Involving 4,5‐Dimethyleneoxazolidin‐2‐ones and a Palladium(0)‐Catalyzed Diaryl Insertion
Author(s) -
Bernal Pablo,
Tamariz Joaquín
Publication year - 2007
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200790148
Subject(s) - chemistry , carbazole , palladium , regioselectivity , adduct , total synthesis , cycloaddition , catalysis , derivative (finance) , intramolecular force , yield (engineering) , medicinal chemistry , stoichiometry , combinatorial chemistry , organic chemistry , economics , metallurgy , materials science , financial economics
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 Pd II ‐stoichiometric cyclization, this new approach comprised an improved cyclization through a more efficient Pd 0 ‐catalyzed intramolecular diaryl coupling which was applied to 9 , thus obtaining the natural carbazole 1 in a higher overall yield.