Direct Access to Fused Salicylaldehydes and Salicylketones from Tetraynes
Direct Access to Fused Salicylaldehydes and Salicylketones from Tetraynes
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从四炔直接制备稠合水杨醛和水杨酮
DOI：
10.1002/chem.201605785
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发表时间：
2017-03-23
影响因子：
4.3
通讯作者：
Wang, Shaowu
中科院分区：
文献类型：
--
作者：
Hu, Yimin;Hu, Yadong;Wang, Shaowu
本文报道了一种由四炔经分子间醛/酮反应和羟基化反应一锅、三步级联反应合成融合多功能化水杨醛和水杨酮的简便方法。丙二酸酯与3-溴-1-丙炔缩合制备目标化合物，得到的2,2-二（1-丙基）丙二酸酯与苯乙基溴交叉偶联得到2,2-二（5-苯基-2,4-戊二基）丙二酸酯，经分子内环化得到双环水杨醛。整个转化过程包括通过分子内和分子间反应生成4个新的C-C键和1个新的c -芳基- o键。该反应易于进行，在温和的条件下进行，并表现出优异的区域选择性。水是一种简单易得的试剂，作为OH源。基于同位素取代实验，提出了一种合理的反应机理。
A facile method for the synthesis of fused, multifunctionalized salicylaldehydes and salicylketones by a onepot, three-step cascade hexadehydro-Diels-Alder (HDDA) reaction of tetraynes followed by an intermolecular aldehyde/ketone reaction and hydroxylation is reported. Target compounds were prepared by the condensation of malonates with 3-bromo-1-propyne, and the resulting 2,2-di(1-propyn3- yl) malonates underwent cross-coupling with phenylethynyl bromides to afford 2,2-di(5-phenyl-2,4-pentadiynyl) malonates, which underwent intramolecular cyclization to produce bicyclic salicylaldehydes. The overall transformation involves the formation of four new C-C bonds and one new C-aryl-O bond through both intramolecular and intermolecular reactions. The reaction is easy to perform, proceeds under mild conditions, and exhibits excellent regioselectivity. Water, a simple and readily available reagent, was employed as the OH source. A plausible reaction mechanism is proposed for this new annulation based on isotopic substitution experiments.