[structure: see text]. A practical, chromotography-free asymmetric synthesis was developed for the large scale preparation of an endothelin receptor antagonist 2. This synthesis includes a new efficient process for the preparation of 6-bromo-2,3-dihydrobenzofuran, a stereoselective conjugate addition of an aryllithium followed by stereospecific addition of the Grignard reagent of the top aryl bromide
[结构:见文字]。开发了一种实用的无色谱不对称合成方法,用于大规模制备内皮素受体拮抗剂2。该合成方法包括制备6-
溴-
2,3-二氢苯并呋喃的新有效方法,即芳基
锂的立体选择性共轭加成。其次是立体定向添加顶部芳基
溴的
格氏试剂,以及
氨基
磷酸介导的立体定向分子内烯醇酸酯烷基化,这导致形成带有三个连续不对称中心的五元环。