Stereoselective allylation of chiral monoperoxyacetals
作者:Aqeel Ahmed、Patrick H. Dussault
DOI:10.1016/j.tet.2005.02.071
日期:2005.5
Neighboring iodo-, alkoxy-, acetoxy- and silyl groups impart useful levels of diastereoselection in the Lewis acid-mediated allylation of monoperoxyacetals. Although monoperoxyacetals are found to be considerably less reactive than corresponding nonperoxidic acetals, similar stereochemical trends are observed in the two series. (c) 2005 Elsevier Ltd. All rights reserved.
Structure elucidation of hypocreolide A by enantioselective total synthesis
作者:Katharina Götz、Johannes C. Liermann、Eckhard Thines、Heidrun Anke、Till Opatz
DOI:10.1039/c001794a
日期:——
The nonenolide hypocreolide A was isolated from culture filtrates of the ascomycete Hypocrea lactea. It exhibits moderate antimicrobial activity against various tested fungi and bacteria. Since neither the relative nor the absolute stereochemistry of the compound could be initially assigned, a stereochemically flexible total synthesis was developed. The two stereogenic centers were formed in high enantioselectivity and yield using transition metal catalyzed asymmetric reactions. While attempts to construct the ten-membered lactone in a ring-closing olefin metathesis gave disappointing results, a combination of cross metathesis and macrolactonization provided the title compound in nine steps and 12% overall yield.
壬烯酚内酯 hypocreolide A 是从升麻菌 Hypocrea lactea 的培养滤液中分离出来的。它对各种受试真菌和细菌具有中等程度的抗菌活性。由于最初无法确定该化合物的相对或绝对立体化学结构,因此开发了一种立体化学灵活的全合成方法。利用过渡金属催化的不对称反应,以高对映选择性和高产率形成了两个立体中心。虽然试图通过闭环烯烃偏析来构建十元内酯的结果令人失望,但交叉偏析和大内酯化相结合的方法在九个步骤中就得到了标题化合物,总收率为 12%。
Indium(III) Chloride Catalyzed Allylation of<i>gem</i>-Diacetates: A Facile Synthesis of Homoallyl Acetates
作者:J. S. Yadav、B. V. Subba Reddy、Ch. Madhuri、G. Sabitha
DOI:10.1246/cl.2001.18
日期:2001.1
Indium(III) chloride is found to catalyze efficiently the allylation of gem-diacetates with allyltrimethylsilane at room temperature to afford the corresponding homoallylic acetates in high yields with good regioselectivity.