Copper-Catalyzed Double Intramolecular Ullmann Coupling for the Synthesis of Diastereomerically and Enantiomerically Pure 4b,9b-Dihydrobenzofuro[3,2-b]benzofurans

Publication Type
Journal contribution (peer reviewed)
Authors
Imrich, H.-G.; Conrad, J.; Beifuss, U.
Year of publication
2015
Published in
Eur. J. Org. Chem.
DOI
10.1002/ejoc.201501132
Page (from - to)
7718-7734
Abstract

The copper-catalyzed double intramolecular Ullmann coupling of syn-1,2-bis(2-bromoaryl)ethane-1,2-diols with catalytic amounts of CuII oxinate as the copper source, K3PO4 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.

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