钯介导的分子内芳基-芳基偶联反应被应用于生物活性天然产物石墨内酯 G ( 1 ) 和棕榈醇 A ( 2 ) 和 B ( 3 )的全合成,它们在 6 上具有不寻常的氯取代基。H- dibenzo[ b , d ]pyran-6-one 骨架。基于偶联反应的过渡态模型,还讨论了芳基-芳基偶联反应区域选择性的机理方面。 全尺寸图像
Total synthesis of masked Alternaria mycotoxins—sulfates and glucosides of alternariol (AOH) and alternariol-9-methyl ether (AME)
摘要:
The synthesis of different protected alternariol derivatives using intramolecular cyclization of iodoresorcylic acid phenyl esters by palladium-catalyzed C-H activation as key step is presented. Furthermore, chemical sulfation and glucosylation were applied for the preparation of conjugated Alternaria mycotoxins. These compounds are suspected to be formed during metabolism in contaminated plants. Therefore, all synthetic conjugates prepared within this work serve as reference materials for further studies in the fields of bioanalytics and toxicology of mycotoxins. (C) 2013 Elsevier Ltd. All rights reserved.
Aminium cation-radical catalysed selective hydration of (<i>E</i>)-aryl enynes
作者:Marie-Claire Giel、Andrew S. Barrow、Christopher J. Smedley、William Lewis、John E. Moses
DOI:10.1039/d1cc02257a
日期:——
The hydration of carbon–carbon triple bonds is an important and atom economic synthetic transformation. Herein, we report a mild and selective method for the catalytic Markovnikov hydration of (E)-aryl enynes to the corresponding enones, mediated through the bench-stable aminium salt, tris(4-bromophenyl)ammoniumyl hexachloroantimonate (TBPA). The chemoselective and diastereoselective method proceeds
碳-碳三键的水合是一种重要的原子经济合成转化。在此,我们报告了一种温和且选择性的催化马尔科夫尼科夫水合 ( E )-芳基烯炔生成相应烯酮的方法,该方法通过稳定的铵盐三(4-溴苯基)六氯锑酸铵 (TBPA) 介导。化学选择性和非对映选择性方法在中性无金属条件下进行,从末端和内部炔烃单元提供出色的产品收率。生物学上重要的 ( E )-3-苯乙烯基异香豆素的合成,包括天然产物 achlisocoumarin III 的正式合成,证明了这种新型转化的效用。
Short and convenient synthesis of two natural phthalides by a copper(I) catalysed Sonogashira/oxacyclisation copper(I) process
Total synthesis of (±)-herbaric acid and (±)-(4-methoxybenzyl)-5,7-dimethoxyphthalide, two natural phthalide products, was achieved in 8 steps and 5 steps, respectively, starting from commercially available 3,5-dimethoxyaniline. The key step of the sequence included a copper-catalysed tandem cross-coupling and oxacylisation reaction of terminal alkynes and 2-iodobenzoïcacid derivatives via 5-exo-dig
A Metal-Free Route to Heterocyclic Trifluoromethyl- and Fluoroalkylselenolated Molecules
作者:Quentin Glenadel、Ermal Ismalaj、Thierry Billard
DOI:10.1021/acs.orglett.7b03338
日期:2018.1.5
A metal-free methodology to easily synthesize various CF3Se-containing heterocyclic compounds has been developed through intramolecular ring closures of alkynes promoted with CF3SeCl. Moreover, this strategy has also been extended to other fluoroalkylselenyl groups.
The chemical synthesis of graphislactones A–D was achieved through the Pd-mediated intramolecular biaryl coupling reaction of phenyl benzoate derivatives.
Convergent Total Synthesis of Paecilomycin B and 6′-<i>epi</i>-Paecilomycin B by a Barbier-Type Reaction Using 2,4,6-Triisopropylphenyllithium
作者:Kiyomi Ohba、Masaya Nakata
DOI:10.1021/acs.joc.7b03041
日期:2018.7.6
The convergent total synthesis of the natural product paecilomycin B and its 6′-epimer was investigated. The aryl-C-glycoside skeleton was constructed by an intramolecular Barbier-type reactionusing 2,4,6-triisopropylphenyllithium and subsequent deoxygenation of the resulting anomeric hydroxy group. Starting from aryl iodide 24, the addition reaction afforded the thermodynamically stable C-β macrocyclic