Total Synthesis of (+)-Batzelladine A and (−)-Batzelladine D via [4 + 2]-Annulation of Vinyl Carbodiimides with <i>N</i>-Alkyl Imines
作者:Michael A. Arnold、Kenneth A. Day、Sergio G. Durón、David Y. Gin
DOI:10.1021/ja063860+
日期:2006.10.1
this strategy, together with additional key steps such as long-range directed hydrogenation and diastereoselective intramolecular iodo-amination, led to highly convergent total syntheses of (-)-batzelladineD and (+)-batzelladine A with excellent stereocontrol.
已经开发出乙烯基碳二亚胺与手性 N-烷基亚胺的非对映选择性 [4 + 2]-环化,以获取 batzelladine 生物碱的立体化学丰富的多环胍核。该策略的应用,连同其他关键步骤,如远程定向氢化和非对映选择性分子内碘胺化,导致 (-)-batzelladine D 和 (+)-batzelladine A 的高度收敛全合成具有出色的立体控制。
Reverse Regioselectivity in the Palladium(II) Thiourea Catalyzed Intermolecular Pauson-Khand Reaction
作者:Na Wu、Lujiang Deng、Lianzhu Liu、Qi Liu、Chuangchuang Li、Zhen Yang
DOI:10.1002/asia.201200783
日期:2013.1
Which way? Palladium thiourea catalyzed Pauson–Khand reaction of norbornene with substituted alkynoates to afford selectively either α‐carboxylated adducts or β‐carboxylated adducts with the reverse regioselectivity has been demonstrated for the first time. Control of the regioselectivity in this transformation is governed by the addition of LiCl. A mechanistic interpretation to account for this observed
Chelation-Based Homologation by Reaction of Organometallic Reagents with O-Alkyl S-Pyridin-2-yl Thiocarbonates: Synthesis of Esters from Grignard Reagents
The one-carbon homologative esterification of Grignardreagents with O-alkyl S-pyridin-2-yl thiocarbonates has been explored. This one-step synthesis of esters from Grignardreagents is the first case to involve chelation-stabilized intermediates.
Catalytic enantioselective access to disubstituted functionalized gem‐difluorocyclopropanes, which are emerging fluorinated motifs of interest in medicinal chemistry, was achieved through asymmetric transferhydrogenation of gem‐difluorocyclopropenyl esters, catalyzed by a Noyori–Ikariya (p‐cymene)‐ruthenium(II) complex, with (N‐tosyl‐1,2‐diphenylethylenediamine) as the chiral ligand and isopropanol
Ru-Based Catechothiolate Complexes Bearing an Unsaturated NHC Ligand: Effective Cross-Metathesis Catalysts for Synthesis of (<i>Z</i>)-α,β-Unsaturated Esters, Carboxylic Acids, and Primary, Secondary, and Weinreb Amides
作者:Zhenxing Liu、Chaofan Xu、Juan del Pozo、Sebastian Torker、Amir H. Hoveyda
DOI:10.1021/jacs.9b02318
日期:2019.5.1
compounds is illustrated through two representative applications: an eight-step, 15% overall yield, and completely Z-selective route leading to an intermediate that may be used in synthesis of stagonolide E (vs 11 steps, 4% overall yield and 91% Z, previously), and a five-step, 25% overall yield sequence to access a precursor to dihydrocompactin (vs 13 steps and 5% overall yield, formerly).
尽管取得了显着进展,但用于制备 (Z)-α,β-不饱和羰基化合物的烯烃复分解方法仍然很少,适用于合成多种生物活性分子。特别需要的是可以由基于钌的催化剂促进的转化,因为这样的实体将允许直接获得羧酸酯和酰胺或酸(与基于钼或钨的亚烷基相反)。在这里,我们详细介绍了如何根据通过计算和实验研究获得的机理洞察,发现一种易于获得的儿茶酚硫合钌配合物,该配合物可用于生成许多 α,β-不饱和羰基化合物,产率高达 81%,≥98: 2 Z/E 比率。我们首次证明,通过使用带有不饱和 N-杂环卡宾 (NHC) 配体的复合物,源自缺电子性更强的酯、酸和 Weinreb 酰胺(相对于伯酰胺或仲酰胺)的产物可以高效合成并具有高度立体化学控制。通过两个代表性应用说明了合成生物活性化合物的新进展的重要性:八步、15% 的总产率和完全 Z 选择性路线,导致可用于合成 stagonolide E 的中间体(vs 11步骤,4%