(±)-vinoxine的全合成是通过Tf 2 O介导的Bischler-Napieralski反应组装多取代的四氢吡啶并[1,2- a ]吲哚骨架来实现的。基于C3位置的一种立体化学,通过自由基环化立体选择性地构建了特征性的二氮杂双环[3.3.1]壬烷骨架。已建立的方法为合成含有多取代吡啶并[1,2- a ]吲哚骨架的天然产物和药物提供了新的选择。
为了合成excelsinidines和mavacurans生物碱,研究了由KHMDS / I 2介导的(+)-geissochizine及其类似物的生物启发性氧化环化作用。应用于Geissoschizine时,N4-C16键的形成导致了Excelsinidines的核心。脂族氮的季铵化是进入马六甲聚糖核心(N1-C16键)所必需的。或者,通过α-氯内酰胺的分子内亲核取代合成17-或excelsinidine。
Bioinspired Divergent Oxidative Cyclizations of Geissoschizine: Total Synthesis of (–)‐17‐nor‐Excelsinidine, (+)‐16‐
<i>epi</i>
‐Pleiocarpamine, (+)‐16‐Hydroxymethyl‐Pleiocarpamine and (+)‐Taberdivarine H
作者:Maxime Jarret、Aurélien Tap、Victor Turpin、Natacha Denizot、Cyrille Kouklovsky、Erwan Poupon、Laurent Evanno、Guillaume Vincent
DOI:10.1002/ejoc.202000962
日期:2020.10.31
To synthesize excelsinidines and mavacurans alkaloids, bio‐inspired oxidativecyclizations of (+)‐geissochizine and analogues mediated by KHMDS/I2 were studied. Applied to geissoschizine, the N4–C16 bond formation led to excelsinidines core. Quaternization of the aliphatic nitrogen was necessary to access the mavacurans core (N1–C16 bond). Alternatively, 17‐nor‐excelsinidine was synthetized via an
为了合成excelsinidines和mavacurans生物碱,研究了由KHMDS / I 2介导的(+)-geissochizine及其类似物的生物启发性氧化环化作用。应用于Geissoschizine时,N4-C16键的形成导致了Excelsinidines的核心。脂族氮的季铵化是进入马六甲聚糖核心(N1-C16键)所必需的。或者,通过α-氯内酰胺的分子内亲核取代合成17-或excelsinidine。
Enantioselective Syntheses of
<i>Strychnos</i>
and
<i>Chelidonium</i>
Alkaloids through Regio‐ and Stereocontrolled Cooperative Catalysis
作者:Luke S. Hutchings‐Goetz、Chao Yang、James W. B. Fyfe、Thomas N. Snaddon
DOI:10.1002/anie.202005151
日期:2020.9.28
We describe enantioselective syntheses of strychnos and chelidonium alkaloids. In the first case, indole acetic acid esters were established as excellent partner nucleophiles for enantioselective cooperative isothiourea/Pd catalyzed α‐alkylation. This provides products containing indole‐bearing stereocenters in high yield and with excellent levels of enantioinduction in a manner that is notably independent
excellent selectivities. This strategy also enabled access to chiral spirocyclohexene‐cyclobutanes and ‐azetidines. Additionally, the obtained scaffolds can undergo diverse transformations leading to complex structures with up to four stereocenters, and we demonstrate that the nitro group, under nucleophilic conditions, can be applied for ring‐opening of the oxetane.
method for peptidethioesters is described using Fmoc solid-phase peptide synthesis (Fmoc-SPPS). This method employs a novel enamide motif to facilitate irreversible intramolecular N-to-S acyl migration, which can efficiently afford the desired peptidethioesters (3 h, 30 °C) under the final trifluoroacetic acid (TFA) cleavage conditions. The acyl-transfer-mediated approach for synthesis of peptide thioesters
Total Syntheses of the Reported Structures of Curcusones I and J through Tandem Gold Catalysis
作者:Yong Li、Mingji Dai
DOI:10.1002/anie.201706845
日期:2017.9.11
Total syntheses of the reported structures of the rhamnofolane diterpene natural products curcusones I and J in racemic form were achieved. The synthetic strategy features a novel tandem gold‐catalyzed furan formation and furan–allene [4+3] cycloaddition to build the 5,7‐fused ring system with an oxa‐bridge in one step, and a stereoselective exo‐Diels–Alder reaction to form the 6‐membered ring. The
实现了外消旋形式的鼠李叶烷二萜天然产物curcusone I和J的报道结构的全合成。该合成策略采用新型串联金催化呋喃形成和呋喃-丙二烯[4+3]环加成,一步构建带有氧杂桥的5,7-稠环系统,以及立体选择性外-狄尔斯-阿尔德反应形成6元环。新开发的串联金催化非常通用并且可以放大。我们的合成表明需要对 curcusones I 和 J 进行结构修改。