作者:Douglas C. Behenna、Justin T. Mohr、Nathaniel H. Sherden、Smaranda C. Marinescu、Andrew M. Harned、Kousuke Tani、Masaki Seto、Sandy Ma、Zoltán Novák、Michael R. Krout、Ryan M. McFadden、Jennifer L. Roizen、John A. Enquist、David E. White、Samantha R. Levine、Krastina V. Petrova、Akihiko Iwashita、Scott C. Virgil、Brian M. Stoltz
DOI:10.1002/chem.201003383
日期:2011.12.9
functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reactionscope, and applications in target‐directed synthesis are reported. Experimental observations suggest that these alkylationreactions occur through an unusual inner‐sphere mechanism involving binding of the prochiral
Selective Synthesis of Cyclooctanoids by Radical Cyclization of Seven-Membered Lactones: Neutron Diffraction Study of the Stereoselective Deuteration of a Chiral Organosamarium Intermediate
作者:Xavier Just-Baringo、Jemma Clark、Matthias J. Gutmann、David J. Procter
DOI:10.1002/anie.201606792
日期:2016.9.26
the few radical syntheses of cyclooctanes. The process is terminated by the quenching of a chiral benzylic samarium. A labeling experiment and neutron diffraction study have been used for the first time to probe the configuration and highly diastereoselective deuteration of a chiral organosamarium intermediate.
七元内酯经过选择性 SmI2 -H2 O 促进的自由基环化形成取代的环辛醇。这些产物是由环化的外切模式产生的,而不是环辛烷的少数自由基合成中通常采用的内切模式。该过程通过手性苄基钐的猝灭而终止。首次使用标记实验和中子衍射研究来探测手性有机钐中间体的构型和高度非对映选择性氘化。
Total Synthesis of the Alleged Structure of Crenarchaeol Enables Structure Revision**
作者:Mira Holzheimer、Jaap S. Sinninghe Damsté、Stefan Schouten、Remco W. A. Havenith、Ana V. Cunha、Adriaan J. Minnaard
DOI:10.1002/anie.202105384
日期:2021.8.2
The 66-membered macrocycle possesses a unique chemical structure featuring 22 mostly remote stereocenters, and a cyclohexane ring connected by a single bond to a cyclopentane ring. Herein we report the first total synthesis of the proposed structure of crenarchaeol. Comparison with natural crenarchaeol allowed us to propose a revised structure of crenarchaeol, wherein one of the 22 stereocenters is
Biocatalytic Conversion of Cyclic Ketones Bearing α-Quaternary Stereocenters into Lactones in an Enantioselective Radical Approach to Medium-Sized Carbocycles
作者:Charlotte Morrill、Chantel Jensen、Xavier Just-Baringo、Gideon Grogan、Nicholas J. Turner、David J. Procter
DOI:10.1002/anie.201800121
日期:2018.3.26
Cyclic ketones bearing α‐quaternary stereocenters underwent efficient kinetic resolution using cyclohexanonemonooxygenase (CHMO) from Acinetobacter calcoaceticus. Lactones possessing tetrasubstituted stereocenters were obtained with high enantioselectivity (up to >99 % ee) and complete chemoselectivity. Preparative‐scale biotransformations were exploited in conjunction with a SmI2‐mediated cyclization
Total Syntheses of (−)-Mersicarpine, (−)-Scholarisine G, (+)-Melodinine E, (−)-Leuconoxine, (−)-Leuconolam, (−)-Leuconodine A, (+)-Leuconodine F, and (−)-Leuconodine C: Self-Induced Diastereomeric Anisochronism (SIDA) Phenomenon for Scholarisine G and Leuconodines A and C
作者:Zhengren Xu、Qian Wang、Jieping Zhu
DOI:10.1021/jacs.5b03619
日期:2015.5.27
Enantioselective total syntheses of title natural products from a common cyclohexenone derivative (S)-18 were reported. Ozonolysis of (S)-18 afforded a stable diketo ester (R)-17 that was subsequently converted to two skeletally different natural products, i.e., (-)-mersicarpine (8) with a [6.5.6.7] fused tetracyclic ring system and (-)-scholarisine G (9) with a [6.5.6.6.5] fused pentacyclic skeleton
报道了来自常见环己烯酮衍生物 (S)-18 的标题天然产物的对映选择性全合成。(S)-18 的臭氧分解提供了稳定的二酮酯 (R)-17,随后将其转化为两种骨架不同的天然产物,即具有 [6.5.6.7] 稠合四环系统的 (-)-mersicarpine (8) 和(-)-scholarisine G (9) 分别具有 [6.5.6.6.5] 融合的五环骨架。通过利用 (+)-melodinine E (6) 向 N-acyliminium 离子 7 的轻松转化,将羟基选择性地引入到 C6、C7、C10 和中央 C21 位置,实现了环化后的多样化。 diazafenestrane 系统,导致 (-)-leuconodine A (11)、(+)-leuconodine F (12)、(-)-scholarisine G (9)、(-)-leuconodine C (13) 和骨骼上不同的 (-