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Naphthoquinone Diels–Alder Reactions: Approaches to the ABC Ring System of Beticolin
Author(s) -
Kramer Carsten S.,
Nieger Martin,
Bräse Stefan
Publication year - 2014
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.201301763
Subject(s) - naphthoquinone , chemistry , cycloaddition , substituent , ring (chemistry) , anthraquinones , diels–alder reaction , yield (engineering) , quinone , stereochemistry , medicinal chemistry , organic chemistry , catalysis , botany , materials science , metallurgy , biology
The syntheses of highly substituted anthraquinones through Diels–Alder reaction by using naphthoquinones are described. As an application, the first synthesis of the ABC tricycle of beticolin 0 ( 1 ) is reported. By using substituted naphthoquinone monoketal dienophiles, the congested quarternary center, the alkenyl methyl group and the oxo‐substituent on the C ring could be established in the desired 1,3‐relationship. By switching to a 1,4‐naphthoquinone dienophile, cycloaddition reaction of sensitive substrates succeed with nearly quantitative yield at moderate temperatures.