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1.
Tetsuhiro Nemoto 《Chemical record (New York, N.Y.)》2019,19(2-3):320-332
In this personal account, our recent studies of novel synthetic methods of 3,4‐fused tricyclic indole derivatives using 3‐alkylidene indoline derivatives as versatile precursors are discussed. Two types of cascade reactions producing 3,4‐fused tricyclic 3‐alkylidene indolines were developed based on a palladium‐catalyzed intramolecular Heck insertion to an allene‐allylic amination cascade and a platinum‐catalyzed intramolecular Friedel‐Crafts type C?H coupling‐allylic amination cascade. Furthermore, three types of 3,4‐fused tricyclic indoles were accessible from a single 3‐alkylidene indoline precursor via acid‐promoted olefin isomerization or oxidative treatments. The application of the developed methods to the synthesis of natural products bearing a 3,4‐fused tricyclic indole skeleton, (?)‐aurantioclavine, fargesine, and synthetic studies of dragmacidin E are also highlighted. 相似文献
2.
Julia Kaufmann Elisabeth Jäckel Dr. Edgar Haak 《Angewandte Chemie (International ed. in English)》2018,57(20):5908-5911
Cascade transformations forming multiple bonds and one‐pot procedures provide rapid access to natural‐product‐like scaffolds from simple precursors. These atom‐economic processes are valuable tools in organic synthesis and drug discovery. Herein, we report on ruthenium‐catalyzed cascade annulations of indole with readily available propargyl alcohols. These provide rapid access to diverse carbazoles, cyclohepta[b]indoles, and further fused polycycles with high selectivity. A bifunctional ruthenium complex featuring a redox‐coupled cyclopentadienone ligand acts as a common catalyst for the different cascade processes. 相似文献
3.
Wentao Liu Wenfang Qin Xiaobei Wang Dr. Fei Xue Prof. Xiao‐Yu Liu Prof. Yong Qin 《Angewandte Chemie (International ed. in English)》2018,57(38):12299-12302
The development of efficient syntheses of complex natural products has long been a major challenge in synthetic chemistry. Designing cascade reactions and employing bioinspired transformations are an important and reliable means of achieving this goal. Presented here is a combination of these two strategies, which allow efficient asymmetric synthesis of the cinchona alkaloid (+)‐cinchonidine. The key steps of this synthesis are a controllable, visible‐light‐induced photoredox radical cascade reaction to efficiently access the tetracyclic monoterpenoid indole alkaloid core, as well as a practical biomimetic cascade rearrangement for the indole to quinoline transformation. The use of stereoselective chemical transformations in this work makes it an efficient synthesis of (+)‐cinchonidine. 相似文献
4.
Total Synthesis of (+)‐Minfiensine: Construction of the Tetracyclic Core Structure by an Asymmetric Cascade Cyclization 下载免费PDF全文
Ze‐Xin Zhang Si‐Cong Chen Prof. Dr. Lei Jiao 《Angewandte Chemie (International ed. in English)》2016,55(28):8090-8094
A new method for one‐step construction of the tetracyclic core structure of the indole alkaloid (+)‐minfiensine was developed utilizing a palladium‐catalyzed asymmetric indole dearomatization/iminium cyclization cascade. An efficient total synthesis of (+)‐minfiensine was realized using this strategy. The present method enables access to the common core structure of a series of monoterpene indole alkaloids, such as vincorine, echitamine, and aspidosphylline A. 相似文献
5.
Organocatalytic Asymmetric Cascade Reactions of 7‐Vinylindoles: Diastereo‐ and Enantioselective Synthesis of C7‐Functionalized Indoles 下载免费PDF全文
Prof. Dr. Feng Shi Hong‐Hao Zhang Xiao‐Xue Sun Jing Liang Tao Fan Prof. Shu‐Jiang Tu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3465-3471
The first catalytic asymmetric cascade reaction of 7‐vinylindoles has been established by the rational design of such substrates. Cascade reactions with isatin‐derived 3‐indolylmethanols in the presence of a chiral phosphoric acid derivative allow the diastereo‐ and enantioselective synthesis of C7‐functionalized indoles as well as the construction of cyclopenta[b]indole and spirooxindole frameworks (all >95:5 d.r., 94–>99 % ee). This approach not only addresses the great challenge of the catalytic asymmetric synthesis of C7‐functionalized indoles, but also provides an efficient method for constructing biologically important cyclopenta[b]indole and spirooxindole scaffolds with excellent optical purity. Investigation of the reaction pathway and activation mode has suggested that this cascade reaction proceeds through a vinylogous Michael addition/Friedel–Crafts process, in which dual H‐bonding activation of the two reactants plays a crucial role. 相似文献
6.
Access to Spiro and Fused Indole Derivatives from α,β‐Unsaturated Aldehydes Enabled by N‐Heterocyclic Carbene Catalysis 下载免费PDF全文
Spiro and fused indoles are attractive heterocyclic compounds with broad and promising activities in various therapeutic fields, and thus, have become the synthetic targets of organic chemists. In this account, we describe our recent progress in the synthesis of a series of spiro and fused indole derivatives through N‐heterocyclic carbene (NHC)‐catalyzed annulations of diverse NHC‐bound intermediates derived from α,β‐unsaturated aldehydes. Particularly, the novel synthesized isatin‐derived α‐bromoenals may be used as versatile 1,3‐biselectrophile synthons for combination with a range of bisnucleophiles for potentially divergent syntheses of skeletally diverse spirooxindoles in the future. 相似文献
7.
Estela Álvarez Dr. Olalla Nieto Faza Dr. Carlos Silva López Dr. Manuel A. Fernández‐Rodríguez Prof. Dr. Roberto Sanz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(37):12889-12893
A cascade reaction of indoles with propargylic diols involving an unprecedented metal‐free 1,2‐indole migration onto an alkyne was carried out. DFT calculations support a mechanism consisting of a concerted nucleophilic attack of the indole nucleus with loss of water, followed by the 1,2‐migration and subsequent Nazarov cyclization. This Brønsted acid‐catalyzed protocol affords indole‐functionalized benzofulvene derivatives in high yields. 相似文献
8.
Cascade Multicomponent Synthesis of Indoles,Pyrazoles, and Pyridazinones by Functionalization of Alkenes 下载免费PDF全文
Dr. Kiran Matcha Dr. Andrey P. Antonchick 《Angewandte Chemie (International ed. in English)》2014,53(44):11960-11964
The development of multicomponent reactions for indole synthesis is demanding and has hardly been explored. The present study describes the development of a novel multicomponent, cascade approach for indole synthesis. Various substituted indole derivatives were obtained from simple reagents, such as unfunctionalized alkenes, diazonium salts, and sodium triflinate, by using an established straightforward and regioselective method. The method is based on the radical trifluoromethylation of alkenes as an entry into Fischer indole synthesis. Besides indole synthesis, the application of the multicomponent cascade reaction to the synthesis of pyrazoles and pyridazinones is described. 相似文献
9.
Synthesis of a Natural Product‐Like Compound Collection through Oxidative Cleavage and Cyclization of Linear Peptides 下载免费PDF全文
Dr. Rico Petersen Dr. Sebastian T. Le Quement Prof. Dr. Thomas E. Nielsen 《Angewandte Chemie (International ed. in English)》2014,53(44):11778-11782
Massive efforts in molecular library synthesis have strived for the development of synthesis methodology which systematically delivers natural product‐like compounds of high spatial complexity. Herein, we present a conceptually simple approach that builds on the power of solid‐phase peptide synthesis to assemble precursor peptides (oligomers) designed to undergo oxidative cascade reactions. By harnessing the structural side‐chain diversity and inherent stereochemical features offered by readily available amino acids (monomers), a proof‐of‐concept collection of 54 skeletally and stereochemically diverse compounds was generated, and selected compounds were elaborated into isoform‐selective metalloprotease inhibitors. 相似文献
10.
Barluenga J Fernández MA Aznar F Valdés C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(8):2276-2283
A novel approach for the synthesis of the important indole ring is described. Indoles are obtained from o-bromoanilines and alkenyl halides in a Pd-catalyzed cascade process that involves an alkenyl amination followed by an intramolecular Heck reaction. The overall process represents the first example of the participation of alkenyl amination reactions in Pd-catalyzed cascade reactions. Initially, the relative reactivity of aryl and alkenyl bromides and chlorides towards Pd-catalyzed amination was investigated. Competition experiments were carried out in the presence of primary and secondary amines, and these revealed the reactivity order alkenyl bromides > aryl bromides > alkenyl chlorides > aryl chlorides, as well as very high chemoselectivity; the more reactive halide was always favored. Thereafter, optimized reaction conditions for the sequential alkenyl amination/Heck cyclization to give indoles were investigated with the model reaction of o-bromoaniline with alpha-bromostyrene. An extensive screening of ligands, bases, and reaction conditions revealed that the [Pd2(dba)3]/DavePhos, NaOtBu, toluene combination at 100 degrees C were the optimized reaction conditions to carry out the cascade process (dba=dibenzylideneacetone, DavePhos=2-dicyclohexylphosphino-2'-N,N-dimethylaminobiphenyl). The reaction proceeds with aryl, alkyl, and functionalized substitutents in both starting reactants. The cyclization was also studied with N-substituted o-bromoanilines (which would give rise to N-substituted indoles); however, in this case, indole formation occurred only with 1-substituted-2-bromoalkenes. Finally, the application of this methodology to o-chloroanilines required further optimization. Although the catalyst based on DavePhos failed to promote the cascade process, a catalytic combination based on [Pd2(dba)3]/X-Phos promoted the formation of the indole ring also from the less reactive chloroanilines. 相似文献
11.
Lei Zhang Ye Zhang Wenting Li Dr. Xiangbing Qi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):5042-5045
A reaction cascade of aza‐Achmatowicz rearrangement followed by indole nucleophilic cyclization was developed to generate the common indole‐fused azabicyclo[3.3.1]nonane core of the macroline family alkaloids. The key to the success of the strategy relies on the careful manipulation of protecting groups and judicious selection of chemoselective furan oxidation conditions. The synthetic utility was further demonstrated on the asymmetric total synthesis of (?)‐alstofolinine A. 相似文献
12.
Nigel M. Groome Elghareeb E. Elboray Dr. Martyn W. Inman Prof. H. Ali Dondas Dr. Roger M. Phillips Colin Kilner Prof. Ronald Grigg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(6):2180-2184
Naturally occurring indole‐3‐carbinol and 3,3‐diindolylmethane show bioactivity in a number of disparate disease areas, including cancer, prompting substantial synthetic analogue activity. We describe a new approach to highly functionalised derivatives that starts from allene gas and proceeds via the combination of a three‐component Pd0‐catalysed cascade with a one‐pot, three‐component carbophilic PtII cascade linked to a stereoselective acid‐catalysed Mannich–Michael reaction that generates complex cyclopropyl diindolylmethanes which show selective activity against prostate cancer cell lines. 相似文献
13.
A palladium-catalyzed direct 2-alkylation reaction of free N-H indoles has been developed. This reaction relies on a norbornene-mediated cascade C-H activation process at the indole ring, which features high regioselectivity and excellent functional group tolerance. The reaction represents the first example for a generally applicable, direct C-H alkylation of indole at the 2-position. 相似文献
14.
We report a unified strategy for the total syntheses of (–)-psychotriasine and (+)-pestalazine B based on the advanced intermediates of 3α-amino-hexahydropyrrolo[2,3-b]indole. To construct these structural motifs, a cascade reaction involving a BINOL-derived phosphoric anion-paired catalyst for enantioselective or diastereoselective azo-coupling/iminium-cyclizations was developed. The remaining key steps of the synthesis involve a sterically hindered amination via hypervalent iodine reagents and the Larock annulation. These transformations enable a general approach to the syntheses of indole alkaloids containing a 3α-amino-hexahydropyrrolo[2,3-b]indole motif and could be further applied to build a natural product-based library. 相似文献
15.
《化学:亚洲杂志》2017,12(23):2975-2979
A highly efficient method for constructing C3‐methyl‐substituted pyrroloindolines and furoindolines via cascade dearomatization reaction of indole derivatives with methyl iodide was developed. This protocol offers a direct approach to a wide range of C3 methyl substituted pyrroloindolines under mild conditions. The utility of this method was further demonstrated in the concise synthesis of (±)‐esermethol. 相似文献
16.
A strategy for the synthesis of 2,3-disubstituted indole derivatives based on an intramolecular carbopalladation-anion capture cascade has been developed, wherein construction of the pyrrole ring and functionalisation of the indole C2 and C3 positions were achieved by extensive use of palladium(0)-catalysed coupling reactions. 相似文献
17.
Stereoselective [3+2] Carbocyclization of Indole‐Derived Imines and Electron‐Rich Alkenes: A Divergent Synthesis of Cyclopenta[b]indole or Tetrahydroquinoline Derivatives 下载免费PDF全文
Alicia Galván Dr. Jonás Calleja Dr. Adán B. González‐Pérez Prof. Dr. Rosana Álvarez Prof. Dr. Angel R. de Lera Prof. Dr. Francisco J. Fañanás Prof. Félix Rodríguez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(47):16769-16774
An unprecedented stereoselective [3+2] carbocyclization reaction of indole‐2‐carboxaldehydes, anilines, and electron‐rich alkenes to obtain cyclopenta[b]indoles is disclosed. This pathway is different from the well‐established Povarov reaction: the formal [4+2] cycloaddition involving the same components, which affords tetrahydroquinolines. Moreover, by simply changing the Brønsted acid catalyst, this multicomponent coupling process could be divergently directed towards the conventional Povarov pathway to produce tetrahydroquinolines or to the new pathway (anti‐Povarov) to generate cyclopenta[b]indoles. Supported by computational studies, a stepwise Mannich/Friedel–Crafts cascade is proposed for the new anti‐Povarov reaction, whereas a concerted [4+2] cycloaddition mechanism is proposed for the Povarov reaction. 相似文献
18.
B. Prabagar Rajendra K. Mallick Rangu Prasad Vincent Gandon Akhila K. Sahoo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2387-2392
A regioselective sulfonyl/sulfinyl migration cycloisomerization cascade of alkyne‐tethered ynamides is developed in the presence of XPhosgold catalyst. This reaction is the first example of a general [1,3]‐sulfonyl migration from the nitrogen center to the β‐carbon atom of ynamides, followed by umpolung 5‐endo‐dig cyclization of the ynamide α‐carbon atom to the gold‐activated alkyne, and final deaurative [1,5]‐sulfinylation. This process allows the synthesis of peripherally decorated unconventional 4‐sulfinylated pyrroles with broad scope from N‐propargyl‐tethered ynamides. In contrast, N‐homopropargyl‐tethered ynamides undergo intramolecular tetradehydro Diels–Alder reaction to provide 2,3‐dihydro‐benzo[f]indole derivatives. Control experiments and density‐functional theory studies were used to study the reaction pathways. 相似文献
19.
Vincent Eschenbrenner‐Lux Dr. Heiko Dückert Dr. Vivek Khedkar Dipl.‐Chem. Hanna Bruss Prof. Dr. Herbert Waldmann Dr. Kamal Kumar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2294-2304
Cascade and domino reactions that proceed through multiple steps in one pot and include multiple bond formations are promising methods for the rapid and efficient generation of complex molecular architectures, including the scaffolds of classes of complex natural product. We describe the development of various one‐pot cascade reaction sequences to yield centrocountins, which are tetracyclic indole derivatives with the basic scaffold of numerous polycyclic alkaloids. The mechanistic investigation of a sequence employing readily available alkynes and 3‐formylchromones as starting materials provided evidence that this one‐pot synthesis proceeds through at least twelve consecutive transformations and includes at least nine different chemical reactions, making it the longest cascade reaction sequence known to date. We describe the scope and limitations of the cascade synthesis approaches and the development of an enantioselectively catalyzed centrocountin synthesis. 相似文献
20.
A Straightforward Approach to Tetrahydroindolo[3,2‐b]carbazoles and 1‐Indolyltetrahydrocarbazoles through [3+3] Cyclodimerization of Indole‐Derived Cyclopropanes 下载免费PDF全文
Dr. Olga A. Ivanova Dr. Ekaterina M. Budynina Prof. Victor N. Khrustalev Dr. Dmitriy A. Skvortsov Dr. Igor V. Trushkov Prof. Mikhail Ya. Melnikov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(4):1223-1227
A rapid new approach to produce biologically relevant bisindoles, namely indolyltetrahydrocarbazoles and indolo[3,2‐b]carbazoles, has been developed, based on the Ga(OTf)3‐catalyzed [3+3] cyclodimerization of indole‐derived donor–acceptor cyclopropanes. Chemoselectivity of the process depends on the location of the three‐membered ring at the indole core. 相似文献