我们全面介绍了头孢菌素B(Tcn-B)的总合成,头孢菌素B(Tcn-B)是一种具有显着抗生素特性的天然糖基化大环内酯。我们的策略是基于我们合成头孢菌素B糖苷配基的经验以及独特的1,2-顺式糖基化步骤。我们使用亚砜异头离去基团结合有远程3- Ô供体上的吡啶甲酸基团允许依赖于H键介导的糖苷配基的高度β-选择性鼠李糖基化和noviosylation。鼠李糖基化的C1-C3片段通过Suzuki-Miyaura交叉偶联固定在C4-C19糖苷配基片段上。环大小选择性的Shiina宏观内酯化提供了一个半糖基化糖苷配基,该糖苷配基直接参与了noviolysation步骤,具有几乎全部的β选择性。最后,设计了一种新颖的脱保护方法,用于去除苯酚上的2-萘基甲基醚,并有效去除所有保护基团,从而提供了合成的tiacumicin B.
我们全面介绍了头孢菌素B(Tcn-B)的总合成,头孢菌素B(Tcn-B)是一种具有显着抗生素特性的天然糖基化大环内酯。我们的策略是基于我们合成头孢菌素B糖苷配基的经验以及独特的1,2-顺式糖基化步骤。我们使用亚砜异头离去基团结合有远程3- Ô供体上的吡啶甲酸基团允许依赖于H键介导的糖苷配基的高度β-选择性鼠李糖基化和noviosylation。鼠李糖基化的C1-C3片段通过Suzuki-Miyaura交叉偶联固定在C4-C19糖苷配基片段上。环大小选择性的Shiina宏观内酯化提供了一个半糖基化糖苷配基,该糖苷配基直接参与了noviolysation步骤,具有几乎全部的β选择性。最后,设计了一种新颖的脱保护方法,用于去除苯酚上的2-萘基甲基醚,并有效去除所有保护基团,从而提供了合成的tiacumicin B.
All‐Carbon [3+3] Oxidative Annulations of 1,3‐Enynes by Rhodium(III)‐Catalyzed CH Functionalization and 1,4‐Migration
作者:David J. Burns、Daniel Best、Martin D. Wieczysty、Hon Wai Lam
DOI:10.1002/anie.201503978
日期:2015.8.17
1,3‐Enynes containing allylic hydrogens cis to the alkyne function as three‐carbon components in rhodium(III)‐catalyzed, all‐carbon [3+3] oxidativeannulations to produce spirodialins. The proposed mechanism of these reactions involves the alkenyl‐to‐allyl 1,4‐rhodium(III) migration.
A key step towards EPC synthesis of (+)-heptelidic acid
作者:Gerhard Riehs、Ernst Urban、Horst Völlenkle
DOI:10.1016/0040-4020(96)00428-0
日期:1996.6
blocks for the EPCsynthesis of the antibiotic (+)-heptelidicacid, was determined by X-ray structure analysis. Conjugate addition of an acetal protected vinylcuprate to the 5′R configurated enoate 3n gave adduct 9n as a single diastereomer in 79% yield. Further, cleavage of the auxiliary and of the acetal protecting group from 9n were studied. Finally, we obtained the silyl protected β-ketoester 13
Ti(II)-mediated domino cyclization of 2-functionalized 1-halo-2,n-enynes (n= 7, 8) to bicyclic compounds
作者:Sentaro Okamoto、Hidemoto Ito、Shogo Tanaka、Fumie Sato
DOI:10.1016/j.tetlet.2006.08.099
日期:2006.10
The reaction of 2-functionalized 1-halo-2,n-enynes (n = 7 or 8) with a divalent titanium reagent, Ti(O-i-Pr)(4)/2i-PrMgCl, proceeded in a domino fashion to afford bicyclic compounds in good yields. (c) 2006 Elsevier Ltd. All rights reserved.
EPC synthesis of (+)-heptelidic acid
作者:G. Riehs、E. Urban
DOI:10.1007/bf00807894
日期:1997.3
An EPC (enantiomerically pure compound) synthesis of the antibiotic natural product (+)-heptelidic acid (1) is presented. Key step of the synthesis is a conjugate addition of the acetal protected vinyl cuprate 4 to the auxiliary shielded enoate 5n which gives the adduct 7n as a single diastereomer. After cleavage of the acetal protecting group and of the chiral auxiliary the enantiomerically pure beta-ketoester 12 has been obtained which has been transformed to the title compound 1 (11 steps starting from 5n, 10.6% overall yield).