Synthesis of polysubstituted furans by palladium-catalyzed coupling of butatrienyl carbinols with aryl halides and triflates
作者:José M. Aurrecoechea、Elena Pérez
DOI:10.1016/j.tet.2004.03.060
日期:2004.5
An efficient one-pot two-step synthesis of polysubstituted furans is described using readily available 4,5-epoxy-2-alkynyl esters as starting materials. In the first step, reduction of these with SmI2 affords buta-1,2,3-trienyl carbinol intermediates which, in the second step, participate in Pd(0)-catalyzed cyclization reactions with aryl halides and triflates by a mechanism probably involving oxidative
描述了使用容易获得的4,5-环氧-2-炔基酯作为起始原料的多取代呋喃的有效的一锅两步合成法。在第一步中,用SmI 2还原这些化合物可得到丁一1,2,3-三烯基甲醇中间体,在第二步中,它可能通过一种涉及以下机理的机制参与Pd(0)催化的与芳基卤化物和三氟甲磺酸酯的环化反应氧化加成,分子内氧化palpalpalation和还原消除步骤。以这种方式,最多四个碳取代基被结合到呋喃环上,其中芳基被引入到呋喃的3-或4-位。这些特征使得该方法特别适合于区域选择性合成四取代的呋喃。