Copper-Catalyzed Double Intramolecular Ullmann Coupling for the Synthesis of Diastereomerically and Enantiomerically Pure 4b,9b-Dihydrobenzofuro[3,2-<i>b</i>]benzofurans
作者:Hans-Georg Imrich、Jürgen Conrad、Uwe Beifuss
DOI:10.1002/ejoc.201501132
日期:2015.12
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
铜催化双分子内双 Ullmann 偶联合成-1,2-双(2-溴芳基)乙烷-1,2-二醇与催化量的 CuII oxinate 作为铜源, K3PO4 作为碱, KI 作为还原剂乙腈水溶液选择性地提供非对映异构和对映异构纯形式的 4b,9b-二氢苯并呋喃 [3,2-b] 苯并呋喃,产率高达 90%。通过相应的(E)-二苯乙烯的催化二羟基化,可以以非对映体和对映体纯形式获得底物。