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1.
Zhen Liu Jiahao Chen Hou‐Xiang Lu Xiaohan Li Yang Gao John R. Coombs Matthew J. Goldfogel Keary M. Engle 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(47):17224-17229
We report the development of palladium(0)‐catalyzed syn‐selective 1,2‐carboboration and ‐silylation reactions of alkenes containing cleavable directing groups. With B2pin2 or PhMe2Si‐Bpin as nucleophiles and aryl/alkenyl triflates as electrophiles, a broad range of mono‐, di‐, tri‐ and tetrasubstituted alkenes are compatible in these transformations. We further describe a directed dearomative 1,2‐carboboration of electron‐rich heteroarenes by employing this approach. Through use of a removable chiral directing group, we demonstrate the viability of achieving stereoinduction in Heck‐type alkene 1,2‐difunctionalization. This work introduces new avenues to access highly functionalized boronates and silanes with precise regio‐ and stereocontrol. 相似文献
2.
Zhen Liu Jiahao Chen Hou‐Xiang Lu Xiaohan Li Yang Gao John R. Coombs Matthew J. Goldfogel Keary M. Engle 《Angewandte Chemie (International ed. in English)》2019,58(47):17068-17073
We report the development of palladium(0)‐catalyzed syn‐selective 1,2‐carboboration and ‐silylation reactions of alkenes containing cleavable directing groups. With B2pin2 or PhMe2Si‐Bpin as nucleophiles and aryl/alkenyl triflates as electrophiles, a broad range of mono‐, di‐, tri‐ and tetrasubstituted alkenes are compatible in these transformations. We further describe a directed dearomative 1,2‐carboboration of electron‐rich heteroarenes by employing this approach. Through use of a removable chiral directing group, we demonstrate the viability of achieving stereoinduction in Heck‐type alkene 1,2‐difunctionalization. This work introduces new avenues to access highly functionalized boronates and silanes with precise regio‐ and stereocontrol. 相似文献
3.
Gold‐Catalyzed Cascade Reactions of Furan‐ynes with External Nucleophiles Consisting of a 1,2‐Rearrangement: Straightforward Synthesis of Multi‐Substituted Benzo[b]furans 下载免费PDF全文
Ning Sun Xin Xie Prof. Dr. Yuanhong Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(24):7514-7519
A gold‐catalyzed cycloisomerization of silyl‐protected 2‐(1‐alkynyl)‐2‐alken‐1‐(2‐furanyl)‐1‐ols with various nucleophiles including water, alcohol, aniline, sulfonamide, and electron‐rich arene has been developed. The method provides a highly efficient access to 5,7‐disubstituted or 2,5,7‐trisubstituted benzo[b]furans with a wide diversity of substituents under mild reaction conditions, which are not easily available by other methods. Remarkably, an interesting rearrangement of the alkyl group from C2 to the C3 position of the furan ring takes place during the cyclization process. The following gold‐assisted allylic substitution enables an elaboration of benzo[b]furans on its side chain of the C5 position with a wide range of functional groups. 相似文献
4.
Reaction between Furan‐ or Thiophene‐2‐carbonyl Chloride,Isocyanides, and Dialkyl Acetylenedicarboxylates: Multicomponent Synthesis of 2,2′‐Bifurans and 2‐(Thiophen‐2‐yl)furans 下载免费PDF全文
Mohammad Hosein Sayahi Mehdi Adib Zeinab Hamooleh Long‐Guan Zhu Massoud Amanlou 《Helvetica chimica acta》2015,98(9):1231-1239
An efficient multi‐component synthesis of highly functionalized 2,2′‐bifurans and 2‐(thiophen‐2‐yl)furans is described. A mixture of furan‐ or thiophene‐2‐carbonyl chloride, an isocyanide, and a dialkyl acetylenedicarboxylate undergoes a smooth addition reaction in dry CH2Cl2 at ambient temperature to produce 2‐amino‐5‐(4‐chlorofuran‐2‐yl)furan‐3,4‐dicarboxylates and 2‐amino‐5‐(4‐chlorothiophen‐2‐yl)furan‐3,4‐dicarboxylates. A single‐crystal X‐ray‐analysis of a derivative conclusively confirms the structure of these 2,2′‐bifurans and 2‐(thiophen‐2‐yl)furans. A novel electrophilic aromatic substitution reaction can justify the formation of the Cl‐substituted furan or thiophene rings. 相似文献
5.
Irreversible endo‐Selective Diels–Alder Reactions of Substituted Alkoxyfurans: A General Synthesis of endo‐Cantharimides 下载免费PDF全文
Robert W. Foster Dr. Laure Benhamou Dr. Michael J. Porter Dr. Dejan‐Krešimir Bučar Prof. Helen C. Hailes Dr. Christopher J. Tame Dr. Tom D. Sheppard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6107-6114
The [4+2] cycloaddition of 3‐alkoxyfurans with N‐substituted maleimides provides the first general route for preparing endo‐cantharimides. Unlike the corresponding reaction with 3H furans, the reaction can tolerate a broad range of 2‐substitued furans including alkyl, aromatic, and heteroaromatic groups. The cycloaddition products were converted into a range of cantharimide products with promising lead‐like properties for medicinal chemistry programs. Furthermore, the electron‐rich furans are shown to react with a variety of alternative dienophiles to generate 7‐oxabicyclo[2.2.1]heptane derivatives under mild conditions. DFT calculations have been performed to rationalize the activation effect of the 3‐alkoxy group on a furan Diels–Alder reaction. 相似文献
6.
《中国化学》2018,36(4):273-279
o‐Carboryne (1,2‐dehydro‐o‐carborane) is a very useful synthon for the synthesis of a variety of carborane‐functionalized molecules. Diels‐Alder reaction of o‐carboryne with furans gave a series of carborane‐fused oxanorbornenes in moderate to high yields using 1‐OTf‐1,2‐C2B10H11 as carboryne precursor. The resultant cycloadducts can undergo hydrogenation, cyclic oxidation, bromination, [4 + 2]/[2 + 2] cycloaddition and nucleophilic ring opening reaction to afford a variety of highly functionalized carboranes that may find applications as useful basic units in medicine and materials science. 相似文献
7.
Julietta Yedoyan Nikolai Wurzer Urszula Klimczak Thomas Ertl Oliver Reiser 《Angewandte Chemie (International ed. in English)》2019,58(11):3594-3598
A palladium‐catalyzed coupling between aryl halides and monocyclopropanated pyrroles or furans has been developed, leading to valuable six‐membered N‐ and O‐heterocycles. As the key step, a selective cleavage of the non‐activated endocyclic C?C bond of the 2‐heterobicyclo‐[3.1.0]hexane framework is achieved. The developed method offers access to highly functionalized piperidines, pyridines, and pyrans that are challenging to access by traditional methods. 相似文献
8.
Optoelectronic and Self‐assembly Properties of Porphyrin Derivatives with Click Chemistry Modification 下载免费PDF全文
Liang Pengxia Zhengcai Du Dr. Dong Wang Prof. Dr. Zhou Yang Huiyun Sheng Shuqiong Liang Hui Cao Wanli He Prof. Dr. Huai Yang 《Chemphyschem》2014,15(16):3523-3529
A series of functionalized porphyrin molecules containing electron‐rich alkynes, synthesized by means of the Sonogashira coupling reaction were further modified by reacting the ethynyl groups with click reagent through a formal [2+2] click reaction. The photophysical and electrochemical properties of the porphyrin derivatives were studied by UV/Vis spectroscopy and cyclic voltammetry. We show that the optoelectronic properties are affected by the click reagent groups and central metal ions. The functionalized porphyrin molecules show strong charge‐transfer (CT) bands in the visible region (near‐IR region) and potent redox activities. Through a phase‐exchange self‐assembly method, the highly organized morphologies were observed by scanning electron microscopy (SEM). The functionalized porphyrin molecules represent an interesting set of candidates for optoelectronic device components. The effect of the metal ions or click reagent groups on the self‐assembly properties were also studied by the UV/Vis spectroscopic titration experiments. 相似文献
9.
A Gold‐Catalyzed Domino Cyclization Enabling Rapid Construction of Diverse Polyheterocyclic Frameworks 下载免费PDF全文
Yi He Dr. Zhenghua Li Dr. Koen Robeyns Prof. Dr. Luc Van Meervelt Prof. Dr. Erik V. Van der Eycken 《Angewandte Chemie (International ed. in English)》2018,57(1):272-276
We report herein an efficient gold(I)‐catalyzed post‐Ugi domino dearomatization/ipso‐cyclization/Michael sequence that enables access to libraries of diverse (hetero)arene‐annulated tricyclic heterocycles. This process affords novel complex polycyclic scaffolds in moderate to good yields from readily available acyclic precursors with excellent chemo‐, regio‐, and diastereoselectivity. The power of this strategy has been demonstrated by the rapid synthesis of 40 highly functionalized polyheterocycles bearing indole, pyrrole, (benzo)furan, (benzo)thiophene, pyrazole, and electron‐rich arene groups in two operational steps. 相似文献
10.
Anita Jonek Stefanie Berger Prof. Dr. Edgar Haak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(48):15504-15511
Ruthenium‐catalyzed allylation–cyclization reactions of cyclic 1,3‐dicarbonyl compounds with 1‐vinyl propargyl alcohols that lead to diverse carbo‐ or heterocyclic products in a one‐pot cascade process are reported. These mechanistically distinct reactions are catalyzed by a single ruthenium(0) complex that contains a redox‐coupled dienone ligand. The reaction pathway strongly depends on the substrate substitution pattern, which determines the mode of activation of the 1‐vinyl propargyl alcohol. The environmentally benign process, which generates water as the only waste product, is of wide scope and allows the atom‐economic synthesis of highly functionalized furans, pyrans, and spirocarbocycles. 相似文献
11.
Direct Metal‐Free Entry to Aminocyclobutenes or Aminocyclobutenols from Ynamides: Synthetic Applications 下载免费PDF全文
Prof. Dr. Benito Alcaide Prof. Dr. Pedro Almendros Carlos Lázaro‐Milla 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(26):8998-9005
The [2+2] cycloaddition of ynamides with the highly polarized reagent Tf2C=CH2 has been developed to regioselectively afford bis(triflyl)aminocyclobutenes in the absence of catalyst under mild conditions. Incidentally, with the ynamides bearing electron‐rich aromatic rings at the C‐terminal, an interesting reactivity switch was observed; a cyclization/hydroxylation sequence yielded 2‐amino‐3‐(triflyl)cyclobut‐2‐enols. Aminocyclobutene construction with addition of alcohols resulted in the formation of aminocyclobutenyl ethers through a cyclization/hydroalkoxylation process. Moreover, the utility of functionalized aminocyclobutenes as precursors for further elaboration was demonstrated with the preparation of α‐amino‐β,γ‐unsaturated ketones and 3‐(triflyl)buta‐1,3‐dien‐2‐amines through 4 π‐electrocyclic ring opening. 相似文献
12.
Desilylation‐Activated Propargylic Transformation: Enantioselective Copper‐Catalyzed [3+2] Cycloaddition of Propargylic Esters with β‐Naphthol or Phenol Derivatives 下载免费PDF全文
Long Shao Ya‐Hui Wang De‐Yang Zhang Prof. Dr. Jie Xu Prof. Dr. Xiang‐Ping Hu 《Angewandte Chemie (International ed. in English)》2016,55(16):5014-5018
A copper‐catalyzed asymmetric [3+2] cycloaddition of 3‐trimethylsilylpropargylic esters with either β‐naphthols or electron‐rich phenols has been realized and proceeds by a desilylation‐activated process. Under the catalysis of Cu(OAc)2?H2O in combination with a structurally optimized ketimine P,N,N‐ligand, a wide range of optically active 1,2‐dihydronaphtho[2,1‐b]furans or 2,3‐dihydrobenzofurans were obtained in good yields and with high enantioselectivities (up to 96 % ee). This represents the first desilylation‐activated catalytic asymmetric propargylic transformation. 相似文献
13.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(35):10661-10665
The ubiquitous use of π‐rich five‐membered heterocycles has driven the development of new methods for their synthesis for more than a century. Here, we disclose a general and reliable reaction manifold for the construction of highly substituted heterocycles through a facile Lewis‐acid‐catalyzed oxetane rearrangement. Notably, this methodology employs a keto‐oxetane motif as a 1,4‐dicarbonyl surrogate, which can be synthesized using robust alkylation or alkenylation reactions, and thus obviates the need to access 1,4‐dicarbonyl compounds via umpoled starting materials. We harnessed this reactivity to generate a broad range of substituted furans and pyrroles, and extended this methodology to produce benzo‐fused versions thereof. 相似文献
14.
Haoyu Tang Donghui Zhang 《Journal of polymer science. Part A, Polymer chemistry》2010,48(11):2340-2350
Single‐walled carbon nanotubes (SWCNTs) have been functionalized with poly(γ‐benzyl‐L ‐glutamate) (PBLG) by ring‐opening polymerizations of γ‐benzyl‐L ‐glutamic acid‐based N‐carboxylanhydrides (NCA‐BLG) using amino‐functionalized SWCNTs (SWCNT‐NH2) as initiators. The SWCNT functionalization has been verified by FTIR spectroscopy and transmission electron microscopy. The FTIR study reveals that surface‐attached PBLGs adopt random‐coil conformations in contrast to the physically absorbed or bulk PBLGs, which exhibit α‐helical conformations. Raman spectroscopic analysis reveals a significant alteration of the electronic structure of SWCNTs as a result of PBLG functionalization. The PBLG‐functionalized SWCNTs (SWCNT‐PBLG) exhibit enhanced solubility in DMF. Stable DMF solutions of SWCNT‐PBLG/PBLG with a maximum SWCNTs concentration of 259 mg L?1 can be readily obtained. SWCNT‐PBLG/PBLG solid composites have been characterized by differential scanning calorimetry, thermogravimetric analysis, wide/small‐angle X‐ray scattering (W/SAXS), scanning electron microscopy, and polarized optical microscopy for their thermal or morphological properties. Microfibers containing SWCNT‐PBLG and PBLG can also be prepared via electrospinning. WAXS characterization reveals that SWCNTs are evenly distributed among PBLG rods in solution and in the solid state where PBLGs form a short‐range nematic phase interspersed with amorphous domains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2340–2350, 2010 相似文献
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16.
Dr. Chun Kiang Chua Prof. Zdeněk Sofer Jan Luxa Prof. Martin Pumera 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8090-8095
Nitrogen functionalization of graphene offers new hybrid materials with improved performance for important technological applications. Despite studies highlighting the dependence of the performance of nitrogen‐functionalized graphene on the types of nitrogen functional groups that are present, precise synthetic control over their ratio is challenging. Herein, the synthesis of nitrogen‐functionalized graphene rich in amino groups by a Bucherer‐type reaction under hydrothermal conditions is reported. The efficiency of the synthetic method under two hydrothermal conditions was examined for graphite oxide produced by Hummers and Hofmann oxidation routes. The morphological and structural properties of the amino‐functionalized graphene were fully characterized. The use of a synthetic method with a well‐known mechanism for derivatization of graphene will open new avenues for highly reproducible functionalization of graphene materials. 相似文献
17.
Jean‐Benoît Giguère Quentin Verolet Prof. Jean‐François Morin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(1):372-381
New p‐type, n‐type, and ambipolar molecules were synthesized from commercially available 4,10‐dibromoanthanthrone dye. Substitution at the 4,10‐ and 6,12‐positions with different electron‐rich and electron‐poor units allowed the modulation of the optoelectronic properties of the molecules. A bis(dicyanovinylene)‐functionalized compound was also prepared with a reduction potential as low as ?50 mV versus Ag+ with a crystalline two‐dimensional lamellar packing arrangement. These characteristics are important prerequisites for air‐stable n‐type organic field‐effect transistor applications. 相似文献
18.
Mijanur Rahaman Molla Dr. Suhrit Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(32):9860-9869
This paper describes the spontaneous vesicular assembly of a naphthalene–diimide (NDI)‐based non‐ionic bolaamphiphile in aqueous medium by using the synergistic effects of π‐stacking and hydrogen bonding. Site isolation of the hydrogen‐bonding functionality (hydrazide), a strategy that has been adopted so elegantly in nature, has been executed in this system to protect these moieties from the bulk water so that the distinct role of hydrogen bonding in the self‐assembly of hydrazide‐functionalized NDI building blocks could be realized, even in aqueous solution. Furthermore, the electron‐deficient NDI‐based bolaamphiphile could engage in donor–acceptor (D–A) charge‐transfer (CT) interactions with a water‐insoluble electron‐rich pyrene donor by virtue of intercalation of the latter chromophore in between two NDI building blocks. Remarkably, even when pyrene was located between two NDI blocks, intermolecular hydrogen‐bonding networks between the NDI‐linked hydrazide groups could be retained. However, time‐dependent AFM studies revealed that the radius of curvature of the alternately stacked D–A assembly increased significantly, thereby leading to intervesicular fusion, which eventually resulted in rupturing of the membrane to form 1D fibers. Such 2D‐to‐1D morphological transition produced CT‐mediated hydrogels at relatively higher concentrations. Instead of pyrene, when a water‐soluble carboxylate‐functionalized pyrene derivative was used as the intercalator, non‐covalent tunable in‐situ surface‐functionalization could be achieved, as evidenced by the zeta‐potential measurements. 相似文献
19.
Dr. Dimitris Kalaitzakis Myron Triantafyllakis Ioanna Alexopoulou Manolis Sofiadis Prof. Dr. Georgios Vassilikogiannakis 《Angewandte Chemie (International ed. in English)》2014,53(48):13201-13205
A highly efficient one‐pot transformation of readily accessible furans into 4‐hydroxy‐2‐cyclopentenones in H2O, using singlet oxygen as oxidant, has been developed. 相似文献
20.
Dr. Mingsheng Xie Dr. Lili Lin Prof. Dr. Xiaoming Feng 《Chemical record (New York, N.Y.)》2017,17(12):1184-1202
In this review, the recent developments in catalytic asymmetric inverse‐electron‐demand hetero‐Diels−Alder reaction, which is recognized as one of the most powerful routes to construct highly functionalized and enantioenriched six‐membered heterocycles, are described. The article is organized on the basis of different kinds of electron‐deficient heterodienes, including α,β‐unsaturated ketones/aldehydes, o‐benzoquinones, α,β‐unsaturated imines, N‐aryl imines, o‐benzoqinone imides, and other aza‐olefins. 相似文献