共查询到20条相似文献,搜索用时 15 毫秒
1.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(5):1385-1389
An efficient photoredox/nickel catalyzed sulfonylation reaction of aryl, heteroaryl, and vinyl halides has been achieved for the first time. This newly developed sulfonylation protocol provides a versatile method for the synthesis of diverse aromatic sulfones at room temperature and shows excellent functional group tolerance. The electrophilic coupling partners are not limited to aryl, heteroaryl, and vinyl bromides and iodides, but also includes less reactive aryl chlorides as suitable substrates for this transformation. 相似文献
2.
Dr. Long Huang Dr. Chen Zhu M. Sc. Liang Yi Dr. Huifeng Yue Dr. Rajesh Kancherla Prof. Dr. Magnus Rueping 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(1):465-472
Chemical transformations based on cascade reactions have the potential to simplify the preparation of diverse and architecturally complex molecules dramatically. Herein, we disclose an unprecedented and efficient method for the cross-coupling of radical precursors, dienes, and electrophilic coupling partners via a photoredox- and nickel-enabled cascade cross-coupling process. The cascade reaction furnishes a diverse array of saturated carbo- and heterocyclic scaffolds, thus providing access to a quick gain in C−C bond saturation. 相似文献
3.
Andrs García‐Domínguez Rahul Mondal Cristina Nevado 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12414-12418
The potential of merging photoredox and nickel catalysis to perform multicomponent alkene difunctionalizations under visible‐light irradiation is demonstrated here. Secondary and tertiary alkyl groups, as well as sulfonyl moieties can be added to the terminal position of the double bond with simultaneous arylation of the internal carbon atom in a single step under mild reaction conditions. The process, devoid of stoichiometric additives, benefits from the use of bench‐stable and easy‐to‐handle reagents, is operationally simple, and tolerates a wide variety of functional groups. 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(11):3126-3130
Herein, the first acceptorless dehydrogenation of tetrahydroquinolines (THQs), indolines, and other related N‐heterocycles, by merging visible‐light photoredox catalysis and cobalt catalysis at ambient temperature, is described. The potential applications to organic transformations and hydrogen‐storage materials are demonstrated. Primary mechanistic investigations indicate that the catalytic cycle occurs predominantly by an oxidative quenching pathway. 相似文献
5.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(13):3748-3752
Reported herein is an unprecedented photocatalytic asymmetric cross‐dehydrogenative coupling reaction between tertiary amines and simple ketones, and it proceeds by synergistic multiple catalysis with substoichiometric amounts of a hydrogen acceptor. This process is enabled by a simple chiral primary amine catalyst through the coupling of a catalytic enamine intermediate and an iminium cation intermediate in situ generated from tetrahydroisoquinoline derivatives by coupled Ru/Co catalysis. 相似文献
6.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(14):4055-4059
Reported herein is the use of S‐perfluoroalkyl sulfilimino iminiums as a new source of RF radicals under visible‐light photoredox catalysis (RF=CF3, C4F9, CF2Br, CFCl2). These shelf‐stable perfluoroalkyl reagents, readily prepared on gram scale from the corresponding sulfoxide using a one‐pot procedure, allow the efficient photoredox‐induced oxyperfluoroalkylation of various alkenes using fac‐Ir(ppy)3 as the photocatalyst. Importantly, spin‐trapping/electron paramagnetic resonance experiments were carried out to characterize all the radical intermediates involved in this radical/cationic process. 相似文献
7.
Fan Song Fang Wang Lei Guo Xiaoliang Feng Yanyan Zhang Lingling Chu 《Angewandte Chemie (International ed. in English)》2020,59(1):177-181
A stereodivergent reductive coupling reaction between allylic carbonates and vinyl triflates to furnish both E‐ and Z‐configured 1,4‐dienes has been achieved by visible‐light‐induced photoredox/nickel dual catalysis. The mild reaction conditions allow good compatibility of both vinyl triflates and allylic carbonates. Notably, the stereoselectivity of this synergistic cross‐electrophile coupling can be tuned by an appropriate photocatalyst with a suitable triplet‐state energy, providing a practical and stereodivergent means to alkene synthesis. Preliminary mechanistic studies shed some light on the coupling step as well as the control of the stereoselectivity step. 相似文献
8.
Adiran deAguirre Ignacio Funes‐Ardoiz Feliu Maseras 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(12):3938-3942
The computational characterization of the full catalytic cycle for the synthesis of indoline from the reaction between iodoacetanilide and a terminal alkene catalyzed by a nickel complex and a photoactive ruthenium species is presented. A variety of oxidation states of nickel, Ni0, NiI, NiII, and NiIII, is shown to participate in the mechanism. Ni0 is necessary for the oxidative addition of the C?I bond, which goes through a NiI intermediate and results in a NiII species. The NiII species inserts into the alkene, but does not undergo the reductive elimination necessary for C?N bond formation. This oxidatively induced reductive elimination can be accomplished only after oxidation to NiIII by the photoactive ruthenium species. All the reaction steps are computationally characterized, and the barriers for the single‐electron transfer steps calculated using a modified version of the Marcus Theory. 相似文献
9.
Miguel Claros Felix Ungeheuer Federico Franco Vlad Martin‐Diaconescu Alicia Casitas Julio Lloret‐Fillol 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):4923-4928
The chemical inertness of abundant and commercially available alkyl chlorides precludes their widespread use as reactants in chemical transformations. Presented in this work is a metallaphotoredox methodology to achieve the catalytic intramolecular reductive cyclization of unactivated alkyl chlorides with tethered alkenes. The cleavage of strong C(sp3)?Cl bonds is mediated by a highly nucleophilic low‐valent cobalt or nickel intermediate generated by visible‐light photoredox reduction employing a copper photosensitizer. The high basicity and multidentate nature of the ligands are key to obtaining efficient metal catalysts for the functionalization of unactivated alkyl chlorides. 相似文献
10.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(9):2518-2521
Carbon–carbon bond cleavage/functionalization is synthetically valuable, and selective carbonyl−C(sp3) bond cleavage/alkynylation presents a new perspective in constructing ynamides, ynoates, and ynones. Reported here is the first alkoxyl‐radical‐enabled carbonyl−C(sp3) bond cleavage/alkynylation reaction by photoredox catalysis. The use of novel cyclic iodine(III) reagents are essential for β‐carbonyl alkoxyl radical generation from β‐carbonyl alcohols, including alcohols with high redox potential ( >2.2 V vs. SCE in MeCN). β‐Amide, β‐ester, and β‐ketone alcohols yield ynamides, ynoates, and ynones, respectively, for the first time, with excellent regio‐ and chemoselectivity under mild reaction conditions. 相似文献
11.
Wang Wang Chao Ding Yangyang Li Zheqi Li Yuqiang Li Long Peng Guoyin Yin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4660-4664
An unprecedented arylboration of unactivated terminal alkenes, featuring 1,n‐regioselectivity, has been achieved by nickel catalysis. The nitrogen‐based ligand plays an essential role in the success of this three‐component reaction. This transformation displays good regioselectivity and excellent functional‐group tolerance. In addition, the incorporation of a boron group into the products provides substantial opportunities for further transformations. Also demonstrated is that the products can be readily transformed into pharmaceutically relevant molecules. Unexpectedly, preliminary mechanistic studies indicate that although the metal migration favors the α‐position of boron, selective and decisive bond formation is favored at the benzylic position. 相似文献
12.
Adrian Tlahuext‐Aca Dr. Matthew N. Hopkinson R. Aleyda Garza‐Sanchez Prof. Dr. Frank Glorius 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(17):5909-5913
Highly selective tandem nucleophilic addition/cross‐coupling reactions of alkynes have been developed using visible‐light‐promoted dual gold/photoredox catalysis. The simultaneous oxidation of AuI and coordination of the coupling partner by photo‐generated aryl radicals, and the use of catalytically inactive gold precatalysts allows for high levels of selectivity for the cross‐coupled products without competing hydrofunctionalization or homocoupling. As demonstrated in representative arylative Meyer–Schuster and hydration reactions, this work expands the scope of dual gold/photoredox catalysis to the largest class of substrates for gold catalysts and benefits from the mild and environmentally attractive nature of visible‐light activation. 相似文献
13.
Huifeng Yue Chen Zhu Rajesh Kancherla Fangying Liu Magnus Rueping 《Angewandte Chemie (International ed. in English)》2020,59(14):5738-5746
Alkynes are an important class of organic molecules due to their utility as versatile building blocks in synthesis. Although efforts have been devoted to the difunctionalization of alkynes, general and practical strategies for the direct hydroalkylation and alkylarylation of terminal alkynes under mild reaction conditions are less explored. Herein, we report a photoredox/nickel dual‐catalyzed anti‐Markovnikov‐type hydroalkylation of terminal alkynes as well as a one‐pot arylalkylation of alkynes with alkyl carboxylic acids and aryl bromides via a three‐component cross‐coupling. The results indicate that the transformations proceed via a new mechanism involving a single‐electron transfer with subsequent energy‐transfer activation pathways. Moreover, steady‐state and time‐resolved fluorescence‐spectroscopy measurements, density functional theory (DFT) calculations, and wavefunction analysis have been performed to give an insight into the catalytic cycle. 相似文献
14.
Johnny W. Lee Katarzyna N. Lee Ming‐Yu Ngai 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(33):11289-11299
Trifluoromethoxy (OCF3) and difluoromethoxy (OCF2H) groups are fluorinated structural motifs that exhibit unique physicochemical characteristics. Incorporation of these substituents into organic molecules is a highly desirable approach used in medicinal chemistry and drug discovery processes to alter the properties of a parent compound. Recently, tri‐ and difluoromethyl ethers have received increasing attention and several innovative strategies to access these valuable functional groups have been developed. The focus of this Minireview is the use of visible‐light photoredox catalysis in the synthesis of tri‐ and difluoromethyl ethers. Recent photocatalytic strategies for the formation of O?CF3, C?OCF3, O?CF2H, and C?OCF2H bonds as well as other transformations leading to the construction of ORF groups are discussed herein. 相似文献
15.
Michael I. Lipschutz T. Don Tilley 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(28):7418-7422
Recently, the development of more sustainable catalytic systems based on abundant first‐row metals, especially nickel, for cross‐coupling reactions has attracted significant interest. One of the key intermediates invoked in these reactions is a NiIII–alkyl species, but no such species that is part of a competent catalytic cycle has yet been isolated. Herein, we report a carbon–carbon cross‐coupling system based on a two‐coordinate NiII–bis(amido) complex in which a NiIII–alkyl species can be isolated and fully characterized. This study details compelling experimental evidence of the role played by this NiIII–alkyl species as well as those of other key NiI and NiII intermediates. The catalytic cycle described herein is also one of the first examples of a two‐coordinate complex that competently catalyzes an organic transformation, potentially leading to a new class of catalysts based on the unique ability of first‐row transition metals to accommodate two‐coordinate complexes. 相似文献
16.
Synthesis of Non‐Classical Arylated C‐Saccharides through Nickel/Photoredox Dual Catalysis 下载免费PDF全文
Dr. Audrey Dumoulin Jennifer K. Matsui Dr. Álvaro Gutiérrez‐Bonet Prof. Gary A. Molander 《Angewandte Chemie (International ed. in English)》2018,57(22):6614-6618
The development of synthetic tools to introduce saccharide derivatives into functionally complex molecules is of great interest, particularly in the field of drug discovery. Herein, we report a new route toward highly functionalized, arylated saccharides, which involves nickel‐catalyzed cross‐coupling of photoredox‐generated saccharyl radicals with a range of aryl‐ and heteroaryl bromides, triggered by an organic photocatalyst. In contrast to existing methods, the mild reaction conditions achieve arylation of saccharide motifs while leaving the anomeric carbon available, thus providing access to a class of arylated glycosides that has been underexplored until now. To demonstrate the potential of this strategy in late‐stage functionalization, a variety of structurally complex molecules incorporating saccharide moieties were synthesized. 相似文献
17.
Long Huang Chen Zhu Liang Yi Huifeng Yue Rajesh Kancherla Magnus Rueping 《Angewandte Chemie (International ed. in English)》2020,59(1):457-464
Chemical transformations based on cascade reactions have the potential to simplify the preparation of diverse and architecturally complex molecules dramatically. Herein, we disclose an unprecedented and efficient method for the cross‐coupling of radical precursors, dienes, and electrophilic coupling partners via a photoredox‐ and nickel‐enabled cascade cross‐coupling process. The cascade reaction furnishes a diverse array of saturated carbo‐ and heterocyclic scaffolds, thus providing access to a quick gain in C?C bond saturation. 相似文献
18.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(15):4054-4058
The first catalytic inverse hydroboration of imines with N‐heterocyclic carbene (NHC) boranes has been realized by means of cooperative organocatalysis and photocatalysis. This catalytic combination provides a promising platform for promoting NHC‐boryl radical chemistry under sustainable and radical‐initiator‐free conditions. The highly important functional‐group compatibility and possible application in late‐stage hydroborations represent an important step forward to an enhanced α‐amino organoboron library. 相似文献
19.
Shorouk O. Badir Audrey Dumoulin Jennifer K. Matsui Prof. Gary A. Molander 《Angewandte Chemie (International ed. in English)》2018,57(22):6610-6613
The incorporation of C‐glycosides in drug design has become a routine practice for medicinal chemists. These naturally occurring building blocks exhibit attractive pharmaceutical profiles, and have become an important target of synthetic efforts in recent decades. 1 Described herein is a practical, scalable, and versatile route for the synthesis of non‐anomeric and unexploited C‐acyl glycosides through a Ni/photoredox dual catalytic system. By utilizing an organic photocatalyst, a range of glycosyl‐based radicals are generated and efficiently coupled with highly functionalized carboxylic acids at room temperature. Distinctive features of this transformation include its mild conditions, impressive compatibility with a wide array of functional groups, and most significantly, preservation of the anomeric carbon: a handle for further, late‐stage derivatization. 相似文献
20.
Wan‐Lei Yu Yong‐Chun Luo Lei Yan Dan Liu Zhu‐Yin Wang Peng‐Fei Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11057-11061
A synergistic catalytic method combining photoredox catalysis, hydrogen‐atom transfer, and proton‐reduction catalysis for the dehydrogenative silylation of alkenes was developed. With this approach, a highly concise route to substituted allylsilanes has been achieved under very mild reaction conditions without using oxidants. This transformation features good to excellent yields, operational simplicity, and high atom economy. Based on control experiments, a possible reaction mechanism is proposed. 相似文献