Ph3PAuNTf2 as a Superior Catalyst for the Selective Synthesis of 2H-Chromenes: Application to the Concise Synthesis of Benzopyran Natural Products
作者:Ioannis N. Lykakis、Christina Efe、Charis Gryparis、Manolis Stratakis
DOI:10.1002/ejoc.201001674
日期:2011.4
Ph3PAuNTf2 (≈1 mol-%) catalyzes the selective cycloisomerization of substituted aryl propargyl ethers into 2H-chromenes in excellent yields. Benzofuran byproducts are formed only in the case of electron-deficient arenes, in up to 7 % relative yield. The Ph3PAuNTf2-catalyzed cyclization of aryl propargyl ethers was applied as a key step to the concise synthesis of the naturally occurring benzopyrans
Ph3PAuNTf2 (≈1 mol-%) 以优异的产率催化取代的芳基炔丙基醚选择性环异构化成 2H-色烯。苯并呋喃副产物仅在缺电子芳烃的情况下形成,相对产率高达 7%。Ph3PAuNTf2 催化的芳炔基醚环化被用作简明合成天然苯并吡喃 seselin、xanthyletin、precocenes I 和 II、8-(3',3'-二甲基烯丙基)wenteria chromene 和 2, 2-二甲基-8-异戊二烯-6-丙烯酸。