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Synthetic Route to 4,4a‐ and 3,4‐Dihydroxanthones through [4+2] Cycloaddition and Base‐Assisted Sigmatropic Rearrangement
Author(s) -
Chernov Nikita M.,
Shutov Roman V.,
Sharoyko Vladimir V.,
Kuz'mich Nikolay N.,
Belyakov Alexander V.,
Yakovlev Igor P.
Publication year - 2017
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.201700310
Subject(s) - chemistry , cycloaddition , sigmatropic reaction , isomerization , lewis acids and bases , computational chemistry , density functional theory , stereochemistry , natural product , combinatorial chemistry , medicinal chemistry , organic chemistry , catalysis
The [4+2] cycloaddition of chromone‐fused dienes with enamines was found to be an efficient method for the synthesis of 4,4a‐ and 3,4‐dihydroxanthone derivatives. Either product type could be obtained by choosing the proper conditions [reaction time and addition of La(NO 3 ) 3 as a Lewis acid]. Calculations using density functional theory and Møller–Plesset perturbation theory showed that the isomerization of 4,4a‐dihydroxanthones to 3,4‐dihydroxanthones occurred through a base‐assisted sigmatropic rearrangement. The described reaction provides a convenient route to a natural‐product‐inspired group of 4,4a‐dihydroxanthones with cytotoxic activity.