Asymmetric Total Synthesis of Aglacins A, B, and E
作者:Mengmeng Xu、Min Hou、Haibing He、Shuanhu Gao
DOI:10.1002/anie.202105395
日期:2021.7.19
An asymmetric photoenolization/Diels–Alder (PEDA) reaction between electron-rich 2-methylbenzaldehydes and unsaturated γ-lactones was developed to directly construct the basic tricyclic core of aryltetralin lactone lignans. This methodology enabled the first asymmetrictotalsynthesis of aglacins A, B, and E and revision of the absolute configuration of these natural lignans. The strategy was also
开发了富电子2-甲基苯甲醛和不饱和γ-内酯之间的不对称光烯醇化/狄尔斯-阿尔德(PEDA)反应,以直接构建芳基四氢萘内酯木脂素的基本三环核心。这种方法实现了 aglacins A、B 和 E 的第一次不对称全合成,并修正了这些天然木脂素的绝对构型。该策略还用于通过四步和六步制备天然存在的芳基二氢萘型木脂素 (-)-7,8-二氢异正义素 B 和 (+)-linoxepin,以及 27 个含有 C8' 的天然产物样分子第四纪中心。我们相信合成的 aglacins 和小分子文库为进行天然产物鬼臼毒素家族的 SAR 研究提供了新的机会。
Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Esters with Chiral Iridium N,P Ligand Complexes
作者:David H. Woodmansee、Marc-André Müller、Lars Tröndlin、Esther Hörmann、Andreas Pfaltz
DOI:10.1002/chem.201202397
日期:2012.10.22
Enantioselective conjugate reduction of a wide range of α,β‐unsaturated carboxylicesters was achieved using chiral Ir N,P complexes as hydrogenation catalysts. Depending on the substitution pattern of the substrate, different ligands perform best. α,β‐Unsaturated carboxylicesters substituted at the α position are less problematic substrates than originally anticipated and in some cases α‐substituted
3-Benzyl-furan-2(5H)-one (2a) and 3-(4-bromobenzyl)-furan-2(5H)-one (2b) were treated with TBDMSOTf and converted into the corresponding tert-butyldimethyl-silylfuran ethers. These furans were further condensed with several aromatic aldehydes affording compounds 5-14 with general 3-benzyl-5-arylidene-furan-2(5H)-one structures in 31% to 98% yields. Such compounds are analogues of the naturally occurring nostoclide lactones, reported to present moderate cytotoxic activity. Compounds 5-14 were submitted to an in vitro bioassay against the HL-60, HCT-8, SF295 and MDA-MB-435 cancer cell lines using the MTT cytotoxicity assay.
Abstract The vinylogous aldol reaction between appropriate aldehydes and furan-based silyloxy diene synthon generated from 3-benzyl-5 H -furan-2-one ( 3 ) afforded two truncated lactone analogues [compounds ( 4 ) and ( 5 )] of nostoclides ( 2 ). The compounds were fully characterized by IR, NMR ( 1 H and 13 C), 2D NMR spectroscopy experiments (HMBC, HSQC and NOESY), MS spectrometry and X-ray crystallography
Disubstituted endo tricyclic lactones have been prepared by the reaction of primary alkylmagnesium compounds with the endo bicyclo[2.2.1]hept-5-ene-2, 3 dicarboxylic anhydride. These lactones were alkylated and transformed into corresponding 3,5,5-trialkyl-2(5H) furanones.