Enantioselective Total Synthesis of (−)-Chlorothricolide via the Tandem Inter- and Intramolecular Diels−Alder Reaction of a Hexaenoate Intermediate
作者:William R. Roush、Richard J. Sciotti
DOI:10.1021/ja980611f
日期:1998.8.1
An enantioselective total synthesis of (−)-chlorothricolide (1) has been completed via a route involving the tandem inter- and intramolecular Diels−Alder (IMDA) reaction of hexaenoate 19 and the chiral dienophile (R)-12. This reaction, which establishes seven asymmetric centers in a single operation, is feasible only by virtue of the high diastereofacial and exo selectivity of dienophile 12. The C(9)-trimethylsilyl
Stereospecific Synthesis of β<sup>3</sup>-Amino Acid Derivatives from Propargylic Alcohols: Efficient Solution-Phase Synthesis of Oligopeptides without Coupling Agents
A stereospecific synthesis of β3‐amino acids has been accomplished starting from readily available and enantioenriched propargylic alcohols. This conversion can be effected in only three steps by selenium‐mediated organic transformations of the carbon–carbon triple bond. This method is especially attractive because the reactive Se‐phenyl selenocarboxylate intermediates can be trapped with the amine
Leukotriene B-4 1 was prepared from two chiral synthons 8 and 14. The chiral secondary alcohols of 8 and 14 were constructed by BINOL/Ti(OiPr)(4) catalyzed enantioselective alkynylzinc addition to aldehydes. (C) 2017 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%。