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Electrocyclization‐Mediated Approach to 2‐Methyltriclisine, an Unnatural Analog of the Azafluoranthene Alkaloid Triclisine
Author(s) -
Silveira Claudio C.,
Larghi Enrique L.,
Mendes Samuel R.,
Bracca Andrea B. J.,
Rinaldi Francieli,
Kaufman Teodoro S.
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200900673
Subject(s) - chemistry , isomerization , claisen rearrangement , alkaloid , yield (engineering) , ether , ring (chemistry) , stereochemistry , organic chemistry , materials science , metallurgy , catalysis
The synthesis of 2‐methyltriclisine, an unnatural analog of the azafluoranthene alkaloid triclisine, is reported. The synthesis was achieved in 10 steps and 21 % overall yield from 2‐bromo‐3,4‐dimethoxybenzaldehyde, through the intermediacy of 3,4‐dimethoxyfluoren‐9‐one. Construction of the heterocyclic ring entailed the para ‐Claisen rearrangement of an allyl‐4‐fluorenyl ether, followed by isomerization of the resulting 2‐allylfluoren‐9‐one and a microwave‐assisted electrocyclization of the aza 6π‐electron system formed by oximation of its carbonyl function. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)