Boron-Mediated Aldol Reaction of Carboxylic Esters: Complementary Anti- and Syn-Selective Asymmetric Aldol Reactions
作者:Tadashi Inoue、Ji-Feng Liu、Dana C. Buske、Atsushi Abiko
DOI:10.1021/jo0257896
日期:2002.7.1
The boron-mediated aldol reaction of carboxylic esters is described in detail. Contrary to the general belief that carboxylic esters are inert under the condition of the boron enolate formation, propionate esters are enolized with certain combinations of a boron triflate and an amine. More importantly, the stereochemical course of the aldol reaction can be controlled by the judicious selection of the
详细描述了硼介导的羧酸酯的羟醛反应。与通常认为羧酸酯在烯醇硼形成的条件下是惰性的一般看法相反,丙酸酯被三氟甲磺酸硼和胺的某些组合烯醇化。更重要的是,可以通过明智地选择烯醇化试剂来控制羟醛反应的立体化学过程。用c-Hex2BOTf和三乙胺处理丙酸酯可制得抗醛醇缩合产物,而用Bu2BOTf和二异丙基乙胺处理丙酸酯可在与醛反应后选择性地生成顺醛醇缩合产物。已经开发了具有结构相关的,容易获得的手性去甲麻黄碱衍生的丙酸酯的互补抗和顺选择性不对称醛醇缩合反应。