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Copper‐Catalyzed Double Intramolecular Ullmann Coupling for the Synthesis of Diastereomerically and Enantiomerically Pure 4b,9b‐Dihydrobenzofuro[3,2‐ b ]benzofurans
Author(s) -
Imrich HansGeorg,
Conrad Jürgen,
Beifuss Uwe
Publication year - 2015
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.201501132
Subject(s) - chemistry , intramolecular force , catalysis , dihydroxylation , copper , acetonitrile , medicinal chemistry , organic chemistry , polymer chemistry , stereochemistry , enantioselective synthesis
The copper‐catalyzed double intramolecular Ullmann coupling of syn ‐1,2‐bis(2‐bromoaryl)ethane‐1,2‐diols with catalytic amounts of Cu II oxinate as the copper source, K 3 PO 4 as a base, and KI as a reductant in aqueous acetonitrile selectively delivers 4b,9b‐dihydrobenzofuro[3,2‐ b ]benzofurans in diastereomerically and enantiomerically pure form and yields of up to 90 %. The substrates can be obtained in both diastereomerically and enantiomerically pure form by catalytic dihydroxylation of the corresponding ( E )‐stilbenes.