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1.
Gonzalo Blay Dr. Isabel Fernández Dr. M. Carmen Muñoz Prof. Dr. José R. Pedro Prof. Dr. Carlos Vila 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(30):9117-9122
Chiral complexes of BINOL‐based ligands with zirconium tert‐butoxide catalyze the Friedel–Crafts alkylation reaction of indoles with β‐trifluoromethyl‐α,β‐unsaturated ketones to give functionalized indoles with an asymmetric tertiary carbon center attached to a trifluoromethyl group. The reaction can be applied to a large number of substituted α‐trifluoromethyl enones and substituted indoles. The expected products were obtained with good yields and ees of up to 99 %. 相似文献
2.
Conjugate addition of indoles to a variety of α,β-unsaturated ketones (chalcones) mediated by a catalytic amount of KHSO4 at room temperature under ultrasonic conditions to afford the corresponding Michael adducts in good to excellent yields was reported. 相似文献
3.
Divergent Reactivity in Palladium‐Catalyzed Annulation with Diarylamines and α,β‐Unsaturated Acids: Direct Access to Substituted 2‐Quinolinones and Indoles
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Dr. Rajesh Kancherla Togati Naveen Prof. Debabrata Maiti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(24):8723-8726
A palladium‐catalyzed C?H activation strategy has been successfully employed for exclusive synthesis of a variety of 3‐substituted indoles. A [3+3] annulation for synthesizing substituted 2‐quinolinones was recently developed by reaction of α,β‐unsaturated carboxylic acids with diarylamines under acidic conditions. In the present work, an analogous [3+2] annulation is achieved from the same set of starting materials under basic conditions to generate 1,3‐disubstituted indoles exclusively. Mechanistic studies revealed an ortho‐palladation–π‐coordination–β‐migratory insertion–β‐hydride elimination reaction sequence to be operative under the reaction conditions. 相似文献
4.
Lei Yang Dr. Qiming Zhu Shengmei Guo Bo Qian Chungu Xia Hanmin Huang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(5):1638-1645
A cooperative catalytic system established by the combination of an iron salt and a chiral Brønsted acid has proven to be effective in the asymmetric Friedel–Crafts alkylation of indoles with β‐aryl α′‐hydroxy enones. Good to excellent yields and enatioselectivities were observed for a variety of α′‐hydroxy enones and indoles, particularly for the β‐aryl α′‐hydroxy enones bearing an electron‐withdrawing group at the para position of the phenyl ring (up to 90 % yield and 91 % ee). The proton of the chiral Brønsted acid, the Lewis acid activation site, as well as the inherent basic site for the hydrogen‐bonding interaction of the Brønsted acid are responsible for the high catalytic activities and enantioselectivities of the title reaction. A possible reaction mechanism was proposed. The key catalytic species in the catalytic system, the phosphate salt of FeIII, which was thought to be responsible for the high activity and good enantioselectivity, was then confirmed by ESIMS studies. 相似文献
5.
Silver‐Mediated Intermolecular 1,2‐Alkylarylation of Styrenes with α‐Carbonyl Alkyl Bromides and Indoles
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Xuan‐Hui Ouyang Dr. Ren‐Jie Song Ming Hu Yuan Yang Prof. Dr. Jin‐Heng Li 《Angewandte Chemie (International ed. in English)》2016,55(9):3187-3191
A new iron‐facilitated silver‐mediated radical 1,2‐alkylarylation of styrenes with α‐carbonyl alkyl bromides and indoles is described, and two new C?C bonds were generated in a single step through a sequence of intermolecular C(sp3)?Br functionalization and C(sp2)?H functionalization across the alkenes. This method provides an efficient access to alkylated indoles with broad substrate scope and excellent selectivity. 相似文献
6.
Marco Bandini Alfonso Melloni Simona Tommasi Achille Umani‐Ronchi 《Helvetica chimica acta》2003,86(11):3753-3763
A new class of α,β‐unsaturated S‐(1,3‐benzoxazol‐2‐yl) thioesters of type 2 have been synthesized and effectively employed as electrophiles in the stereoselective alkylation of indoles. The combination of electronic as well as steric properties of such Michael acceptors allowed us to carry out Friedel? Crafts alkylations of various substituted indoles in the presence of a catalytic amount (20 mol‐%) of chiral cationic [PdII(Tol‐binap)] complexes. With the optimized catalytic system (PdCl2(MeCN)2/Tol‐binap/AgSbF6), the desired β‐indolyl‐substituted thioderivatives 4 were obtained in good yield, with an enantiomeric excess (ee) of up to 86%. The remarkable versatility of the enantiomerically enriched thioesters 4 was demonstrated by quantitatively transforming them into optically active β‐indolyl esters and amides under mild conditions. With this stereoselective, catalytic Friedel? Crafts reaction, we open up the way towards new α,β‐unsaturated compounds that could be suitable candidates for the preparation of a number of optically active β‐substituted carboxylic compounds. 相似文献
7.
Junxian Yang Zheng Wang Zeyuan He Guofeng Li Liang Hong Wangsheng Sun Rui Wang 《Angewandte Chemie (International ed. in English)》2020,59(2):642-647
The first asymmetric synthesis of tetrasubstituted α‐amino allenoates by a chiral phosphoric acid catalyzed dearomative γ‐addition reaction of 2,3‐disubstituted indoles to β,γ‐alkynyl‐α‐imino esters is reported. This method provides access to a series of highly functionalized tetrasubstituted allenes featuring quaternary stereocenters in high yields, and with excellent regio‐, diastereo‐, and enantioselectivities under mild conditions without by‐product formation. Representative large‐scale reactions and diverse transformations of the products into various scaffolds with potential biological activities render are also disclosed. The mechanism of the reaction was elucidated by control reactions and DFT calculations. 相似文献
8.
Can Liu Tao Miao Lei Zhang Prof. Pinhua Li Yicheng Zhang Prof. Lei Wang 《化学:亚洲杂志》2014,9(9):2584-2589
A novel and efficient palladium‐catalyzed C2 arylation of N‐substituted indoles with 1‐aryltriazenes for the synthesis of 2‐arylindoles was developed. In the presence of BF3 ? OEt2 and palladium(II) acetate (Pd(OAc)2), N‐substituted indoles reacted with 1‐aryltriazenes in N,N‐dimethylacetamide (DMAC) to afford the corresponding aryl–indole‐type products in good to excellent yields. 相似文献
9.
Catalytic Asymmetric Synthesis of 3‐Indolyl Methanamines Using Unprotected Indoles and N‐Boc Imines under Basic Conditions
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Prof. Dr. Takayoshi Arai Junki Kakino 《Angewandte Chemie (International ed. in English)》2016,55(49):15263-15267
A chiral imidazolidine‐containing NCN/Pd‐OTf catalyst ( C4 ) promoted the nucleophilic addition of unprotected indoles to N‐Boc imines. Using sulfinyl amines as the N‐Boc imine precursors, the combined use of C4 with K2CO3 activated the NH indoles to give chiral 3‐indolyl methanamines with up to 98 % ee. Compared with conventional acid‐catalyzed Friedel–Crafts reactions, this reaction proceeds under mildly basic conditions and is advantageous for the use of acid‐sensitive substrates. 相似文献
10.
Ruthenium(II)‐Catalyzed C−H Activation of Imidamides and Divergent Couplings with Diazo Compounds: Substrate‐Controlled Synthesis of Indoles and 3H‐Indoles
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Yunyun Li Dr. Zisong Qi Dr. He Wang Xifa Yang Prof. Xingwei Li 《Angewandte Chemie (International ed. in English)》2016,55(39):11877-11881
Indoles are an important structural motif that is commonly found in biologically active molecules. In this work, conditions for divergent couplings between imidamides and acceptor–acceptor diazo compounds were developed that afforded NH indoles and 3H‐indoles under ruthenium catalysis. The coupling of α‐diazoketoesters afforded NH indoles by cleavage of the C(N2)?C(acyl) bond whereas α‐diazomalonates gave 3H‐indoles by C?N bond cleavage. This reaction constitutes the first intermolecular coupling of diazo substrates with arenes by ruthenium‐catalyzed C?H activation. 相似文献
11.
Asymmetric Synthesis of Furo[3,4‐b]indoles by Catalytic [3+2] Cycloaddition of Indoles with Epoxides
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Dr. Lili Lin Xiao Yuan Songsong Guo Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15104-15107
A highly efficient N,N′‐dioxide–NiII catalyst system for the catalytic [3+2] cycloaddition of indoles with epoxides through C?C cleavage of oxiranes was accomplished under mild conditions. It provided a promising approach for chiral furo[3,4‐b]indoles in up to 98 % yield with up to 91 % enantiomeric excess (ee) and >95:5 diastereomeric ratio (d.r.). 相似文献
12.
Daniel Clare Benjamin C. Dobson Phillip A. Inglesby Christophe Aïssa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16344-16348
The functionalization of aryl and heteroaryls using α‐carbonyl sulfoxonium ylides without the help of a directing group has remained so far a neglected area, despite the advantageous safety profile of sulfoxonium ylides. Described herein are the cyclizations of α‐carbonyl sulfoxonium ylides onto benzenes, benzofurans and N‐p‐toluenesulfonyl indoles in the presence of a base in HFIP, whereas pyrroles and N‐methyl indoles undergo cyclization in the presence of an iridium catalyst. Significantly, these two sets of conditions are chemospecific for each groups of substrates. 相似文献
13.
Organocatalytic Asymmetric Cascade Reactions of 7‐Vinylindoles: Diastereo‐ and Enantioselective Synthesis of C7‐Functionalized Indoles
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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
14.
《应用有机金属化学》2017,31(12)
In the presence of a catalytic amount of KI combined with oxidant m CPBA, a convenient catalytic procedure is developed for the preparation of 3‐selanylindoles from indoles and diselenides. In this protocol, KI is first oxidized by m CPBA into hypoiodous acid, which reacts with diselenide to cleave Se‐Se bond. The in situ generated active electrophilic selenium species then reacts with indole, affording 3‐selanylindole via an electrophilic substitution mechanism. This catalytic selenation of indoles has mild reaction conditions and is a simple procedure, which extends the synthetic application of KI in organic synthesis. 相似文献
15.
Wenzhong Huang Lingli Nang Xiangguang Li Lin Yuan Yinhai Ma Deqiang Liang 《中国化学》2015,33(10):1167-1172
Under the catalysis of only 3 mol% of Br2 at room temperature, indoles reacted rapidly with isatins to form biologically important 3,3‐bis(indole‐3‐yl)indoline‐2‐(1H)‐ones with high efficiency and wide substrate scope. Moreover, we demonstrated that p‐toluenesulfonic acid (TsOH) could serve as a surrogate to catalyze this transformation. 相似文献
16.
A new dual palladium/scandium catalysis starting from β‐alkynyl ketones and o‐alkynyl anilines is reported for the first time, leading to the atom‐economic synthesis of rotationally hindered C3‐naphthylated indoles in moderate to good yields and high regioselectivity. This method can tolerate normal air conditions, and features the use of palladium/scandium cooperative catalysts without any ligand, facile double annulation involving various internal alkynes, and good functional group tolerance. 相似文献
17.
Shambabu Joseph Maddirala Vidya S. Gokak Linganagouda D. Basanagoudar 《Journal of heterocyclic chemistry》2004,41(1):7-11
3‐Benzylindole‐2‐carbohydrazides (4) on reaction with triethylorthoformate in a polar solvent like DMF yielded only 10‐benzyl‐1,2‐dihydro‐1‐oxo‐1,2,4‐triazino[4,5‐a]indoles (5) while (4) on reaction with triethylorthoacetate in DMF yielded both 10‐benzyl‐4‐methyl‐1,2‐dihydro‐1‐oxo‐1,2,4‐triazino[4,5‐a]indoles (5) and 3‐benzyl‐2‐(5‐methyl‐1,3,4‐oxadiazol‐2‐yl)indoles (6) instead of only the triazinoindoles as expected. The oxadiazolylindoles (6) were also synthesized by refluxing (4) with excess of orthoesters. The structures of the compounds formed were characterized by their analytical and spectral data. 相似文献
18.
Organocatalytic Asymmetric Arylative Dearomatization of 2,3‐Disubstituted Indoles Enabled by Tandem Reactions
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Yu‐Chen Zhang Jia‐Jia Zhao Fei Jiang Si‐Bing Sun Prof. Feng Shi 《Angewandte Chemie (International ed. in English)》2014,53(50):13912-13915
The organocatalytic asymmetric arylative dearomatization of indoles was achieved through two tandem approaches involving 2,3‐disubstituted indoles and quinone imine ketals. One approach utilized the enantioselective cascade 1,4 addition/alcohol elimination reaction, the other employed the one‐pot tandem arylative dearomatization/transfer hydrogenation sequence. In both cases, enantiomerically pure indole derivatives that bear an all‐carbon quaternary stereogenic center were generated in high yields and excellent stereoselectivities (all d.r.>95:5, up to 99 % ee). 相似文献
19.
Synthesis and biological evaluation of various tricyclic and tetracyclic indoles are described. A number of these compounds possess in vitro activity against human nasopharyngeal carcinoma (HONE‐1) and gastric adenocarcinoma (NUGC‐3) cell lines. 相似文献
20.
Biswanath Das Nikhil Chowdhury K. Damodar K. Ravinder Reddy 《Helvetica chimica acta》2007,90(2):340-345
A simple, mild, rapid, and highly efficient method for the conjugate addition of 1H‐indoles to electron‐deficient olefins has been developed using NaHSO4 ? SiO2 as heterogeneous catalyst. The conversion proceeds at room temperature, and the corresponding Michael adducts are formed in good‐to‐excellent yields. 相似文献