Asymmetric Synthesis of (−)-7-Epiaustraline and (+)-1,7-Diepiaustraline
摘要:
A diastereoselective and modular approach to the synthesis of the 3-hydroxymethyl-2,3,5,6,7,7a-hexahydro-1H-pyrrolizine-1,2,7-triol structure, characteristic of several natural pyrrolizidine natural products, has been developed. This approach culminated in the synthesis of (-)-7-epiaustraline and (+)-1,7-diepiaustraline. The oxazolidinone group has been found to be a useful protecting group in the RCM reaction and, as part of a pyrrolo[1,2-c]oxazol-3-one ring system, has functioned as a stereo- and regio-directing group in a key diastereoselective cis-dihydroxylation reaction and a regioselective nucleophilic ring-opening of a S,S-dioxo-dioxathiole.
Dual Palladium(II)/Tertiary Amine Catalysis for Asymmetric Regioselective Rearrangements of Allylic Carbamates
作者:Johannes Moritz Bauer、Wolfgang Frey、René Peters
DOI:10.1002/chem.201600138
日期:2016.4.11
access to enantiopure allylicamines as valuable precursors towards chiral β‐ and γ‐aminoalcohols as well as α‐ and β‐aminoacids is desirable for industrial purposes. In this article an enantioselective method is described that transforms achiral allylic alcohols and N‐tosylisocyanate in a single step into highly enantioenriched N‐tosyl protected allylicamines via an allylic carbamate intermediate
Efficient diastereoselective synthesis of a new class of azanucleosides: 2′-homoazanucleosides
作者:Jakob Bouton、Kristof Van Hecke、Serge Van Calenbergh
DOI:10.1016/j.tet.2017.05.083
日期:2017.7
Azanucleosides, sugar-modified nucleosideanalogues containing a 4' nitrogen atom, have shown a lot of therapeutic potential, e.g. as anti-cancer and antiviral agents. We report the synthesis of a series of 2'-homoazanucleosides, in which the nucleobase is attached to the 2'-position of the pyrrolidine ring via a methylene linker. A suitable orthogonally protected iminosugar was synthesized by ring
Dynamic Kinetic Asymmetric Transformation of Diene Monoepoxides: A Practical Asymmetric Synthesis of Vinylglycinol, Vigabatrin, and Ethambutol
作者:Barry M. Trost、Richard C. Bunt、Rémy C. Lemoine、Trevor L. Calkins
DOI:10.1021/ja000547d
日期:2000.6.1
The ability to perform a dynamickineticasymmetrictransformation (DYKAT) using the palladium-catalyzed asymmetric allylic alkylation (AAA) is explored in the context of butadiene monoepoxide. The versatility of this commercially available, but racemic, four-carbon building block becomes significantly enhanced via conversion of both enantiomers into a single enantiomeric product. The concept is explored
stereoisomers with literature data for the natural product, the configuration of the previously unassigned stereocenters at C9 and C20 of haliclamide could be determined to be S for both carbons. The absolute configuration of haliclamide thus is 2S, 9S, 14R, 20S. The antiproliferative activity of synthetic haliclamide against several human cancer cell lines was found to be in the high μM range. The
在环化的基础上,通过闭环烯烃复分解合成了海洋天然产物卤代酰胺。使用用于组装二烯前体以进行复分解反应的四个结构单元中的两个的任一种的对映异构体,还制备了卤代酰胺的三种非天然异构体。根据各个立体异构体的1 H和13 C NMR光谱与天然产物的文献数据进行比较,可以确定先前未分配的卤代酰胺的C9和C20立体中心的构型对于两个碳都是S。因此,卤代酰胺的绝对构型为2 S,9 S,14 R,20 S。发现合成的哈利酰胺对几种人癌细胞系的抗增殖活性处于高μM范围内。该化合物没有抗真菌或抗生素活性。