Stereoselective synthesis of exocyclic allenes by double hydride reduction of 3-alkynyl-2-cycloalkenones
作者:Matthew A. Gubbels、Martin Hulce、John M. Kum、Andrew K. Urick、Eric M. Villa
DOI:10.1016/j.tet.2016.07.058
日期:2016.10
Exocyclic allene natural products and pharmaceutical agents are rare but interesting compounds: Fucoxanthin, grasshopper ketone, and analogues of prostacyclins, cephalosporins, antithrombic agents and sterol biosynthesis inhibitors are representative. Syntheses of exocyclic allenes commonly rely on extended conjugate additions to e.g., alk-2-en-4-ynones, syn SN2′-like additions to alkynyl oxiranes
环外丙二烯天然产物和药物是稀有但有趣的化合物:褐藻黄质,蚱酮和前列环素,头孢菌素,抗血栓剂和固醇生物合成抑制剂的类似物是代表性的。环外烯丙基的合成通常依赖于扩展的共轭加成,例如,alk-2-en-4-ynones,syn S N炔基肟基的2'样加成,以及炔丙基硅烷的亲电取代等取代反应。我们报告说3-炔基-2-环烯酮与2当量的各种氢铝酸盐而不是氢硼酸盐的反应是通过非对映选择性的1,4-还原乙烯基炔丙基中间体醇盐进行的,以提供环外烯丙基为主要产物。还观察到异构的3-炔基环烷醇。