Total Syntheses of the Monoterpene Indole Alkaloids (±)-Alstilobanine A and E and (±)-Angustilodine
作者:Yiqing Feng、Max M. Majireck、Steven M. Weinreb
DOI:10.1021/jo402495q
日期:2014.1.3
developed culminating in stereoselectivetotal syntheses of the small class of unusual monoterpenoid indole alkaloids exemplified by alstilobanines A (3) and E (2) and angustilodine (1). A pivotal step includes a novel intermolecular Michael-type addition of an indole ester dianion to a piperidine-derived nitrosoalkene to form the C15, C16 bond of the alkaloids. In addition, an application of the Romo
作者:Christoph Etling、Giada Tedesco、Anna Di Marco、Markus Kalesse
DOI:10.1021/jacs.3c01262
日期:2023.3.29
discovery of illisimonin A in 2017 extended the structural repertoire of the Illicium sesquiterpenoids─a class of natural products known for their high oxidation levels and neurotrophic properties─with a new carbon backbone combining the strained trans-pentalene and norbornane substructures. We report an asymmetric totalsynthesis of (−)-illisimonin A that traces its tricyclic carbon framework back to a spirocyclic
2017 年 illisimonin A 的发现扩展了八角倍半萜类化合物的结构库——一类以其高氧化水平和神经营养特性而闻名的天然产物——具有结合了紧张的反戊二烯和降冰片烷子结构的新碳主链。我们报告了 (−)-illisimonin A 的不对称全合成,将其三环碳骨架追溯到由串联-Nazarov/ene 环化产生的螺环前体。作为螺环关键中间体和 illisimonin A 之间的关键环节,一种合成三环 [5.2.1.0 1,5的新方法]癸烷通过自由基环化进行了探索。该方法应用于由 Ti(III) 介导的环化和 semipinacol 重排组成的两阶段策略,以获取天然产物的碳主链。这些关键步骤与精心策划的 C-H 氧化相结合,以建立致密的氧化模式。
Modelling nucleophilic substitution at silicon in solution, using hypervalent silicon compounds based on 2-pyridones
作者:Alan R. Bassindale、Moheswar Borbaruah、Simon J. Glynn、David J. Parker、Peter G. Taylor
DOI:10.1039/a904402g
日期:——
complexes has been determined from the 29Si chemical shift usingmodelcompounds for the tetracoordinate and pentacoordinate limiting cases. Correlation of the % Si–O bond formation with % pentacoordination enables the pathway for substitution at silicon to be mapped in solution. The generality of these techniques is examined using a series of related aromatic ligands.