共查询到20条相似文献,搜索用时 15 毫秒
1.
Dr. Yinan Zhang Dr. Qing Ye Dr. Xiachang Wang Prof. Qing‐Bai She Prof. Jon S. Thorson 《Angewandte Chemie (International ed. in English)》2015,54(38):11219-11222
The first enantioselective total synthesis of griseusin A, griseusin C, 4′‐deacetyl‐griseusin A, and two non‐native counterparts in 11–14 steps is reported. This strategy highlights a key hydroxy‐directed C? H olefination of 1‐methylene isochroman with an α,β‐unsaturated ketone followed by subsequent stereoselective epoxidation and regioselective cyclization to afford the signature tetrahydro‐spiropyran ring. Colorectal cancer cell cytotoxicities of the final products highlight the impact of the griseusin tetrahydro‐spiropyran ring on bioactivity. As the first divergent enantioselective synthesis, the strategy put forth sets the stage for further griseusin mechanism‐of‐action and SAR studies. 相似文献
2.
Synthesis of Pyrrolophenanthridine Alkaloids Based on C(sp3)H and C(sp2)H Functionalization Reactions 下载免费PDF全文
Dr. Chihiro Tsukano Nobusuke Muto Iderbat Enkhtaivan Prof. Yoshiji Takemoto 《化学:亚洲杂志》2014,9(9):2628-2634
Assoanine, pratosine, hippadine, and dehydroanhydrolycorine belong to the pyrrolophenanthridine family of alkaloids, which are isolated from plants of the Amaryllidaceae species. Structurally, these alkaloids are characterized by a tetracyclic skeleton that contains a biaryl moiety and an indole core, and compounds belonging to this class have received considerable interest from researchers in a number of fields because of their biological properties and the challenges associated with their synthesis. Herein, a strategy for the total synthesis of these alkaloids by using C? H activation chemistry is described. The tetracyclic skeleton was constructed in a stepwise manner by C(sp3)? H functionalization followed by a Catellani reaction, including C(sp2)? H functionalization. A one‐pot reaction involving both C(sp3)? H and C(sp2)? H functionalization was also attempted. This newly developed strategy is suitable for the facile preparation of various analogues because it uses simple starting materials and does not require protecting groups. 相似文献
3.
A General and Scalable Synthesis of Aeruginosin Marine Natural Products Based on Two Strategic C(sp3)H Activation Reactions 下载免费PDF全文
David Dailler Dr. Grégory Danoun Prof. Dr. Olivier Baudoin 《Angewandte Chemie (International ed. in English)》2015,54(16):4919-4922
An efficient and scalable access to the aeruginosin family of marine natural products, which exhibit potent inhibitory activity against serine proteases, is reported. This synthesis was enabled by the strategic use of two different, recently implemented C(sp3)? H activation reactions. The first method led to the common 2‐carboxy‐6‐hydroxyoctahydroindole (Choi) core of the target molecules on a large scale, whereas the second one provided rapid and divergent access to the various hydroxyphenyllactic (Hpla) subunits. This strategy allowed the synthesis of the aeruginosins 98B and 298A, with the latter being obtained in unprecedentedly large quantities. 相似文献
4.
Prof. Dr. K. C. Nicolaou Dr. Philipp Heretsch Dr. Abdelatif ElMarrouni Christopher R. H. Hale Dr. Kiran K. Pulukuri Dr. Avinash K. Kudva Dr. Vivek Narayan Prof. Dr. K. Sandeep Prabhu 《Angewandte Chemie (International ed. in English)》2014,53(39):10443-10447
A catalytic asymmetric total synthesis of the potent and selective antileukemic Δ12‐prostaglandin J3 (Δ12‐PGJ3) is described. The convergent synthesis proceeded through intermediates 2 and 3 , formed enantioselectively from readily available starting materials and coupled through an aldol reaction followed by dehydration to afford stereoselectively the cyclopentenone alkylidene structural motif of the molecule. 相似文献
5.
David Dailler Dr. Grégory Danoun Benjamin Ourri Prof. Dr. Olivier Baudoin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(26):9370-9379
A general and scalable access to the aeruginosin family of marine natural products, exhibiting potent inhibitory activity against serine proteases, is reported. This was enabled by the strategic use of two recently implemented Pd‐catalyzed C(sp3)?H activation reactions. The first method allowed us to obtain the common 2‐carboxy‐6‐hydroxyoctahydroindole (Choi) core of the target molecules on a large scale, whereas the second method provided a rapid and divergent access to various hydroxyphenyllactic (Hpla) subunits, including halogenated ones. This unique strategy, together with an optimization of the fragment coupling sequence allowed the synthesis of four aeruginosins, that is, 98A–C and 298A from the chiral pool. Among them, aeruginosin 298A was synthesized on an unprecedentedly large scale. In addition, halogenated aeruginosins 98A and 98C were synthesized for the first time, thanks to a fine‐tuning of the final hydrogenation step. 相似文献
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A Concise and Scalable Strategy for the Total Synthesis of Dictyodendrin B Based on Sequential CH Functionalization 下载免费PDF全文
Andrew K. Pitts Dr. Fionn O'Hara Dr. Robert H. Snell Prof. Matthew J. Gaunt 《Angewandte Chemie (International ed. in English)》2015,54(18):5451-5455
A sequential C? H functionalization strategy for the synthesis of the marine alkaloid dictyodendrin B is reported. Our synthesis begins from commercially available 4‐bromoindole and involves six direct functionalizations around the heteroarene core as part of a gram‐scale strategy towards the natural product. 相似文献
8.
Spiroacetal Formation through Telescoped Cycloaddition and Carbon–Hydrogen Bond Functionalization: Total Synthesis of Bistramide A 下载免费PDF全文
Xun Han Prof. Paul E. Floreancig 《Angewandte Chemie (International ed. in English)》2014,53(41):11075-11078
Spiroacetals can be formed through a one‐pot sequence of a hetero‐Diels–Alder reaction, an oxidative carbon–hydrogen bond cleavage, and an acid treatment. This convergent approach expedites access to a complex molecular subunit which is present in numerous biologically active structures. The utility of the protocol is demonstrated through its application to a brief synthesis of the actin‐binding cytotoxin bistramide A. 相似文献
9.
Pentafulvene for the Synthesis of Complex Natural Products: Total Syntheses of (±)‐Pallambins A and B 下载免费PDF全文
Christian Ebner Prof. Dr. Erick M. Carreira 《Angewandte Chemie (International ed. in English)》2015,54(38):11227-11230
The first total syntheses of pallambins A and B are enabled by the use of pentafulvene in an unprecedented Diels–Alder reaction. After elaboration of the adduct through chemoselective cyclopropanation, strategic C? H insertion affords the dense tetracyclic core of the natural products. 1,3‐Dipolar cycloaddition and palladium(II)‐catalyzed alkoxycarbonylation were leveraged for the construction of the hexacyclic scaffold en route to both natural products. 相似文献
10.
Synthesis of Prenyl‐ and Geranyl‐Substituted Carbazole Alkaloids by DIBAL‐H Promoted Reductive Pyran Ring Opening of Dialkylpyrano[3,2‐a]carbazoles 下载免费PDF全文
Ronny Hesse Dr. Olga Kataeva Dr. Arndt W. Schmidt Prof. Dr. Hans‐Joachim Knölker 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(31):9504-9509
The DIBAL‐H promoted reductive pyran ring opening of dialkylpyrano[3,2‐a]carbazoles provides a direct access to a broad range of prenyl‐ and geranyl‐substituted carbazoles. Formation of a pyran ring followed by reductive ring opening represents a new method for the introduction of prenyl and geranyl groups. In the course of the present work, we achieved the first total syntheses of the following eight carbazole alkaloids: clauraila‐E, 7‐hydroxyheptaphylline, 7‐methoxyheptaphylline, mukoenine‐B (clausenatine‐A), mukoenine‐A (girinimbilol), mahanimbinol (mahanimbilol), euchrestine‐A, and isomurrayafoline‐B. 相似文献
11.
Qilin Li Prof. Dr. Hongbin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(46):16379-16382
In this paper, a new strategy towards the synthesis of codeine and morphine is reported. This new approach features a cascade cyclization to construct the dihydrofuran ring, and an intramolecular palladium catalyzed C?H olefination of unactivated aliphatic alkene to install the morphinan ring system. 相似文献
12.
Prof. Dr. Ian Paterson Mengyang Xuan Dr. Stephen M. Dalby 《Angewandte Chemie (International ed. in English)》2014,53(28):7286-7289
As a potent neurotrophic agent, the sesquiterpenoid jiadifenolide represents a valuable small‐molecule lead for the potential therapeutic treatment of neurodegenerative diseases. A stereocontrolled total synthesis of this densely functionalized natural product is reported, central to which is an adventurous samarium‐mediated cyclization reaction to establish the tricyclic core and the adjacent C5 and C6 quaternary stereocenters. 相似文献
13.
Rhodium(III)‐Catalyzed Intramolecular Redox‐Neutral Annulation of Tethered Alkynes: Formal Total Synthesis of (±)‐Goniomitine 下载免费PDF全文
Dr. Bing Zhou Dr. Juanjuan Du Dr. Yaxi Yang Prof. Yuanchao Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12768-12772
A RhIII‐catalyzed intramolecular redox‐neutral atom‐economic annulation of a tethered alkyne has been developed to efficiently construct 2‐amidealkyl indoles with completely reversed regioselectivity by a C?H activation pathway. Furthermore, using the RhIII‐catalyzed C?H activation/annulation as a key step, a one‐pot synthesis of pyrido[1,2‐a]indoles has also been developed and applied to a highly efficient formal total synthesis of (±)‐goniomitine. 相似文献
14.
Corrigendum: Diastereo‐ and Enantioselective Intramolecular C(sp3)H Arylation for the Synthesis of Fused Cyclopentanes 下载免费PDF全文
Dr. Nicolas Martin Cathleen Pierre Dr. Michaël Davi Dr. Rodolphe Jazzar Prof. Dr. Olivier Baudoin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(39):12341-12341
15.
Total Synthesis of 7‐ and 8‐Oxygenated Pyrano[3,2‐a]carbazole and Pyrano[2,3‐a]carbazole Alkaloids via Boronic Acid‐Catalyzed Annulation of the Pyran Ring 下载免费PDF全文
Dr. Konstanze K. Julich‐Gruner Dr. Olga Kataeva Dr. Arndt W. Schmidt Prof. Dr. Hans‐Joachim Knölker 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8536-8540
The boronic acid‐catalyzed annulation of citral opens up a short route to oxygenated cyclized monoterpenoid pyranocarbazole alkaloids. Thus, murrayamine‐D is available in only three steps and 55% overall yield from the corresponding carbazole precursor. 相似文献
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Unprecedented Transformation of a Directing Group Generated In Situ and Its Application in the One‐Pot Synthesis of 2‐Alkenyl Benzonitriles 下载免费PDF全文
Ravi Kumar Rajesh K. Arigela Dr. Bijoy Kundu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11807-11812
An unprecedented protocol for the transformation of benzoyl azides into benzonitrile derivatives via iminophosphoranes generated in situ is described. The strategy was successfully applied to the de‐novo synthesis of 2‐alkenylated benzonitrile derivatives from benzoyl azides through ortho C?H activation/alkenylation followed by subsequent rearrangement. The salient features of this protocol involve incorporation of two important functionalities through cyanation and olefination in one pot under mild reaction conditions by using a less expensive Ru catalyst. The mechanism was established by isolating and characterising (using 31P NMR) an intermediate with two ortho functionalities, iminophosphorane and olefin, under specific reaction conditions. 相似文献
18.
Back Cover: Total Synthesis of 7‐ and 8‐Oxygenated Pyrano[3,2‐a]carbazole and Pyrano[2,3‐a]carbazole Alkaloids via Boronic Acid‐Catalyzed Annulation of the Pyran Ring (Chem. Eur. J. 28/2014) 下载免费PDF全文
Dr. Konstanze K. Julich‐Gruner Dr. Olga Kataeva Dr. Arndt W. Schmidt Prof. Dr. Hans‐Joachim Knölker 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8808-8808
19.
CH Functionalization/Asymmetric Michael Addition Cascade Enabled by Relay Catalysis: Metal Carbenoid Used for CC Bond Formation 下载免费PDF全文
Dr. Dian‐Feng Chen Feng Zhao Yue Hu Prof. Dr. Liu‐Zhu Gong 《Angewandte Chemie (International ed. in English)》2014,53(40):10763-10767
A combination of either ruthenium(II) or rhodium(II) complexes and quinine‐derived squaramide enables 3‐diazooxindoles, indoles, and nitroalkenes to undergo highly efficient asymmetric three‐component reactions, thus affording optically active 3,3′‐bis(indole)s through a consecutive C? C bond‐forming sequence, which turned out to be applicable to the facile total synthesis of (?)‐folicanthine. 相似文献
20.
Copper‐Catalyzed Coupling of Oxime Acetates with Sodium Sulfinates: An Efficient Synthesis of Sulfone Derivatives 下载免费PDF全文
Xiaodong Tang Liangbin Huang Yanli Xu Jidan Yang Dr. Wanqing Wu Prof. Dr. Huanfeng Jiang 《Angewandte Chemie (International ed. in English)》2014,53(16):4205-4208
Sulfone derivatives are important synthetic intermediates. However, the general method for their preparation is through traditional coupling reaction: the alkylation of sodium sulfinates with phenacyl halides. Based on our previous work on sodium sulfinates and oxime acetates, we herein report a novel method for sulfone derivatives by oxidative coupling with sodium sulfinates and oxime acetates using copper as catalyst. The sulfonylvinylamine products could be formed in excellent yields. Upon hydrolysis by silica gel in CH2Cl2, β‐ketosulfones could also be efficiently constructed. Various sulfonylvinylamines and β‐ketosulfones were obtained in good to excellent yields under the optimized reaction conditions. Mechanistic studies indicated that this transformation involved copper‐catalyzed N? O bond cleavage, activation of a vinyl sp2 C? H bond, and C? S bond formation. The oxime acetates act as both a substrate and an oxidant, thus the reaction needs no additional oxidants or additives. 相似文献