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

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

Imrich, H.-G.; Conrad, J.; Beifuss, U.

Erscheinungsjahr

2015

Veröffentlicht in

Eur. J. Org. Chem.

DOI

10.1002/ejoc.201501132

Seite (von - bis)

7718-7734

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, 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.