Syntheses of Strychnine, Norfluorocurarine, Dehydrodesacetylretuline, and Valparicine Enabled by Intramolecular Cycloadditions of Zincke Aldehydes
作者:David B. C. Martin、Lucas Q. Nguyen、Christopher D. Vanderwal
DOI:10.1021/jo2020246
日期:2012.1.6
base-mediated intramolecular Diels–Alder cycloadditions of tryptamine-derived Zincke aldehydes is described. This important complexity-generating transformation provides the tetracyclic core of many indole monoterpene alkaloids in only three steps from commercially available starting materials and played a key role in short syntheses of norfluorocurarine (five steps), dehydrodesacetylretuline (six steps), valparicine
Gold-Catalyzed Asymmetric Thioallylation of Propiolates via Charge-Induced Thio-Claisen Rearrangement
作者:Hanbyul Kim、Jiwon Jang、Seunghoon Shin
DOI:10.1021/jacs.0c09783
日期:2020.12.9
A gold(I)-catalyzedenantioselective thioallylation of propiolates with allyl sulfides is described. The key mechanistic element is a sulfonium-induced Claisenrearrangement which helps minimize the allyl dissociation and render higher enantioselectivity. This protocol features remarkable scope of the allyl moiety, allowing enantiocontrolled synthesis of all-carbon quaternary centers, and exhibits
Rare Example of Nucleophilic Substitution at Vinylic Carbon with Inversion: Mechanism of Methyleneaziridine Formation by Sodium Amide Induced Ring Closure Revisited
作者:Jason J. Shiers、Michael Shipman、Jerome F. Hayes、Alexandra M. Z. Slawin
DOI:10.1021/ja0482684
日期:2004.6.1
(Z)-2-bromobut-2-enylamines by the pendant nitrogen atom leads to 2-ethyleneaziridines by way of stereochemical inversion at the vinylic carbon atom. The stereochemistry of the products is unambiguously established by X-ray crystallography performed on two derivatives. These cyclizations represent some of the first examples of substitution with inversion in unactivated vinylic substrates. In conjunction
(E)- 和 (Z)-2-bromobut-2-enylamines 的 C-Br 键被侧氮原子的分子内亲核取代通过在乙烯基碳原子上的立体化学反转产生 2-亚乙基氮丙啶。产物的立体化学是通过对两种衍生物进行的 X 射线晶体学明确确定的。这些环化代表了在未活化的乙烯基底物中进行反转取代的一些第一个例子。结合额外的氘标记实验,该反应的公认机制被证明是有缺陷的。
New approach to Strychnos alkaloids. Stereocontrolled total synthesis of (.+-.)-dehydrotubifoline
作者:John M. Fevig、Robert W. Marquis、Larry E. Overman
DOI:10.1021/ja00013a068
日期:1991.6
We report a conceptually newapproach to Strychnos alkaloids, which is characterized by the concise evolution of the strychnan skeleton by «aza-Cope-Mannich» rearrangement of a 2-azabicyclo[3.2.1]octane precursor
Studies towards total synthesis of antillatoxin: Investigation of the indium-mediated allylation reactions of carbonyl compounds with β-bromocrotylbromide in water
作者:Teck-Peng Loh、Guo-Qiang Cao、Jian Pei
DOI:10.1016/s0040-4039(97)10826-7
日期:1998.3
Indium mediates the coupling of β-bromocrotylbromide with carbonylcompounds in saturated ammonium chloride in the presence of lanthanide triflate under sonication to give the corresponding compounds in good yield and moderate to high syn diastereoselectivity.