三种天然芳香倍半萜,(−)-表球醇、(−)-4β,7α-aromadendranediol 和 (−)-4α,7α-aromadendranediol,仅通过七个步骤合成,总产率为 12%、15% 和 17%,分别通过立体发散金(I)催化的级联反应从( E , E )-金合欢醇制备,一步形成三环芳香树烷核心。这些是这些天然化合物的最短全合成。
Total Synthesis of <i>ent</i>-Dioxepandehydrothyrsiferol via a Bromonium-Initiated Epoxide-Opening Cascade
作者:Jessica Tanuwidjaja、Sze-Sze Ng、Timothy F. Jamison
DOI:10.1021/ja9052366
日期:2009.9.2
In the first totalsynthesis of ent-dioxepandehydrothyrsiferol, the signature trans-anti-trans 7,7,6-fused tricyclic polyether framework was constructed in a single bromonium-initiated epoxide-openingcascade that incorporates both endo- and exo-selective epoxide openings, each directed by the substitution pattern of the epoxide (methyl groups). This study thus demonstrates the feasibility of a possible
Enantioselective Inhibition of Squalene Synthase by Aziridine Analogues of Presqualene Diphosphate
作者:Ali Koohang、Jessica L. Bailey、Robert M. Coates、Hans K. Erickson、David Owen、C. Dale Poulter
DOI:10.1021/jo100718z
日期:2010.7.16
and N-(α-methylene)bishomogeranyl substituents as mimics for the 2,6,10-trimethylundeca-2,5,9-trienyl side chain of PSPP. The 2R,3S diphosphate enantiomer bearing the N-bishomogeranyl substituent corresponding in absolute stereochemistry to PSPP proved to be the most potent inhibitor (IC50 1.17 ± 0.08 μM in the presence of inorganic pyrophosphate), a value 4-fold less than that of its 2S,3R stereoisomer
角鲨烯合酶通过环丙基羰基中间体、角鲨烯二磷酸 (PSPP)催化两分子 ( E , E )-法呢基二磷酸转化为角鲨烯。由于这种新反应构成了甾醇生物合成的第一个关键步骤,因此对该过程的立体化学和机制以及酶的选择性抑制剂的设计产生了相当大的兴趣和研究。本文报告了 PSPP 的五种外消旋和两种对映纯氮丙啶类似物的合成和表征,并评估了它们作为重组酵母角鲨烯合酶抑制剂的效力。关键的氮丙啶-2-甲醇中间体(6 - OH、7- OH和8 -OH)通过以下方式获得N-烷基化或通过(±)-、(2 R ,3 S )- 和 (2 S ,3 R )-2,3-氮丙啶法尼醇( 9 - OH)的N-酰化-还原序列保护为叔-丁基二甲基甲硅烷基醚。相应的甲磺酸盐与焦磷酸根和甲二膦酸根阴离子的S N 2 置换得到带有N-十一烷基、N-双香叶基和N- (α-亚甲基)双香叶基取代基的氮丙啶 2-二磷酸甲酯和甲二膦酸,作为 2,6,10-
Biomimetic Synthesis of Acid-Sensitive (−)-Caparrapi Oxide and (+)-8-Epicaparrapi Oxide Induced by Artificial Cyclases
[reaction: see text] Asymmetric total syntheses of acid-sensitive (-)-caparrapi oxide (1) and (+)-8-epicaparrapi oxide (2) from farnesol (9) were achieved using Sharpless-Katsuki epoxidation and Lewis acid-assisted chiral Bronsted acid (chiral LBA)-induced polyenecyclization as key steps. Furthermore, (-)-1 could be directly synthesized from (S)-nerolidol (3) and (R)-LBA with 88% ds by reagent control
Stereochemical investigations on the biosynthesis of achiral (<i>Z</i>)-γ-bisabolene in <i>Cryptosporangium arvum</i>
作者:Jan Rinkel、Jeroen S Dickschat
DOI:10.3762/bjoc.15.75
日期:——
A newly identified bacterial (Z)-γ-bisabolene synthase was used for investigating the cyclisation mechanism of the sesquiterpene. Since the stereoinformation of both chiral putative intermediates, nerolidyl diphosphate (NPP) and the bisabolyl cation, is lost during formation of the achiral product, the intriguing question of their absolute configurations was addressed by incubating both enantiomers
From a red alga Laurencia okamurai (10R̃, 11R̃)-(+)-squalene-10, 11-epoxide 1̃ was isolated and its asymmetricsynthesis has been achieved starting from trans, trans-farnesol.