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Highly Selective Three‐Step Synthesis of Rhein in Chloroaluminate Molten Salt: Preclusion of the Hayashi Rearrangement
Author(s) -
Gonnot Vanessa,
Antheaume Cyril,
Nicolas Marc,
Mioskowski Charles,
Baati Rachid
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.200900960
Subject(s) - chemistry , yield (engineering) , molten salt , selectivity , salt (chemistry) , organic chemistry , medicinal chemistry , combinatorial chemistry , inorganic chemistry , catalysis , materials science , metallurgy
An expeditious, three‐step synthesis of rhein ( 2 ) was optimized starting from bis( N , N ‐diethyl)‐5‐methoxybenzene‐1,3‐dicarboxamide. The key final step, involving deprotection/cyclization of ortho ‐benzoylbenzoic acid 9 in acidic chloroaluminate molten salts, yielded the desired natural product with high selectivity and good overall yield by precluding the competitive Hayashi rearrangement.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)