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1.
Dr. Lanting Xu Chao Zhang Dr. Yupeng He Dr. Lushi Tan Prof. Dr. Dawei Ma 《Angewandte Chemie (International ed. in English)》2016,55(1):321-325
An efficient rhodium‐catalyzed method for direct C? H functionalization at the C7 position of a wide range of indoles has been developed. Good to excellent yields of alkenylation products were observed with acrylates, styrenes, and vinyl phenyl sulfones, whereas the saturated alkylation products were obtained in good yield with α,β‐unsaturated ketones. Both the N‐pivaloyl directing group and the rhodium catalyst proved to be crucial for high regioselectivity and conversion. 相似文献
2.
Readily Removable Directing Group Assisted Chemo‐ and Regioselective C(sp3)H Activation by Palladium Catalysis
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Yun‐Fei Zhang Prof. Dr. Hong‐Wei Zhao Hui Wang Jiang‐Bo Wei Prof. Dr. Zhang‐Jie Shi 《Angewandte Chemie (International ed. in English)》2015,54(46):13686-13690
Currently used directing groups for selective aliphatic β‐functionalization of carbonyl compounds show excellent reactivity and selectivity with an amide as a linker. Described herein is 2‐piconimide, used for the first time with commercially available 2‐picolinamide/2‐picolic acid as precursors, to direct C? H arylation/alkenylation by palladium catalysis. The directing group is essential for promoting the sequnetial primary and secondary C(sp3)? H arylation with different aryl iodides in one substrate. The directing group was easily removed under simple reaction conditions at room temperature. 相似文献
3.
Yunus Taskesenligil Ferruh Lafzi Haydar Kilic Nurullah Saracoglu 《Journal of heterocyclic chemistry》2019,56(12):3289-3296
Pd(II)‐catalyzed C‐H arylations of 5‐aminoindole using iodobenzenes as aryl source was studied. Despite pivalamide directing group at 5‐position of the indole, the direct C2‐arylation of the indole observed in high yields and with high regioselectivity. 相似文献
4.
Ir(III)‐Catalyzed C7‐Position‐Selective Oxidative CH Alkenylation of Indolines with Alkenes in Air
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An efficient method for C7‐position‐selective alkenylation of N‐substituted indolines with alkenes is reported. Various 7‐alkenylindolines were obtained in moderate to excellent yields in air in the presence of catalytic amounts of [Cp*IrCl2]2, AgOTf, and Cu(OAc)2. The protocol relies on the use of a carbonyl or carbamoyl group on the nitrogen atom of indoline as a directing group and is potentially applicable to the synthesis of 7‐alkenylindoles and 7‐alkylindoles. 相似文献
5.
Yun‐Fei Zhang Prof. Dr. Hong‐Wei Zhao Hui Wang Jiang‐Bo Wei Prof. Dr. Zhang‐Jie Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(46):13890-13894
Currently used directing groups for selective aliphatic β‐functionalization of carbonyl compounds show excellent reactivity and selectivity with an amide as a linker. Described herein is 2‐piconimide, used for the first time with commercially available 2‐picolinamide/2‐picolic acid as precursors, to direct C H arylation/alkenylation by palladium catalysis. The directing group is essential for promoting the sequnetial primary and secondary C(sp3) H arylation with different aryl iodides in one substrate. The directing group was easily removed under simple reaction conditions at room temperature. 相似文献
6.
Pravas Dolui Jayabrata Das Hediyala B. Chandrashekar S. S. Anjana Debabrata Maiti 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(39):13911-13915
C?H functionalization of aliphatic carboxylic acids without attaching exogenous auxiliary has been so far limited at the proximal β‐position. In this work, we demonstrate a ligand enabled palladium catalyzed first regioselective distal γ‐C(sp3)?H functionalization of aliphatic carboxylic acids without incorporating an exogenous directing group. Aryl iodides containing versatile functional groups including complex organic molecules are well tolerated with good to excellent yields during the γ‐C(sp3)?H arylation reaction. Interestingly, weak coordination of carboxylate group can be further extended for sequential hetero di‐arylation. Application of the protocol has been showcased by synthesizing substituted α‐tetralone. Mechanistic investigations have been carried out to shed light on the reaction pathway. 相似文献
7.
Alkenylation of C(sp3)−H Bonds by Zincation/Copper‐Catalyzed Cross‐Coupling with Iodonium Salts
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Dr. Chuan Liu Prof. Dr. Qiu Wang 《Angewandte Chemie (International ed. in English)》2018,57(17):4727-4731
α‐Vinylation of phosphonates, phosphine oxides, sulfones, sulfonamides, and sulfoxides has been achieved by selective C?H zincation and copper‐catalyzed C(sp3)?C(sp2) cross‐coupling reaction using vinylphenyliodonium salts. The vinylation transformation proceeds in high efficiency and stereospecificity under mild reaction conditions. This zincative cross‐coupling reaction represents a general alkenylation strategy, which is also applicable for α‐alkenylation of esters, amides, and nitriles in the synthesis of β,γ‐unsaturated carbonyl compounds. 相似文献
8.
Steven Bloom Desta Doro Bume Cody Ross Pitts Prof. Dr. Thomas Lectka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8060-8063
To expand upon the recent pioneering reports of catalyzed sp3 C?H fluorination methods, the next rational step is to focus on directing “radical‐based fluorination” more effectively. One potential solution entails selective C?C bond activation as a prelude to selective fluorination. Herein, we report the tandem photocatalyzed ring‐opening/fluorination reactions of cyclopropanols by 1,2,4,5‐tetracyanobenzene (TCB) and Selectfluor to afford a process tantamount to site‐selective β‐fluorination of carbonyl‐containing compounds. This new approach provides a synthetically mild and operationally simple route to otherwise difficult‐to‐prepare β‐fluorinated products in good yields and with good‐to‐excellent regioselectivity. Remarkably, substrates that contain other usually reactive (e.g., benzylic) sites undergo ring‐opening fluorination preferably. The versatility of this method to give cyclic β‐fluorides from tertiary cyclopropanols and γ‐fluoro alcohols is also highlighted. 相似文献
9.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(52):16777-16781
A mild, oxidant‐free, and selective Cp*CoIII‐catalyzed amidation of thioamides with robust dioxazolone amidating agents via C(sp3)−H bond activation to generate the desired amidated products is reported. The method is efficient and allows for the C−H amidation of a wide range of functionalized thioamides with aryl‐, heteroaryl‐, and alkyl‐substituted dioxazolones under the Cp*CoIII‐catalyzed conditions. The observed regioselectivity towards primary C(sp3)−H activation is supported by computational studies and the cyclometalation is proposed to proceed by means of an external carboxylate‐assisted concerted metalation/deprotonation mechanism. The reported method is a rare example of the use of a directing group other than the commonly used pyridine and quinolone classes for Cp*CoIII‐catalyzed C(sp3)−H functionalization and the first to exploit thioamides. 相似文献
10.
Yandong Dou Kenry Dr. Jiang Liu Jianze Jiang Prof. Qing Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(28):6896-6901
o-Alkenylation of unprotected phenols has been developed by direct C−H functionalization catalyzed by PdII. This work features phenol group as a directing group and realizes highly site-selective C−H bond functionalization of phenols to achieve the corresponding products in moderate to excellent yields at 60 °C. The advantages of this reaction include unprecedented C−H functionalization using phenol as a directing group, high regioselectivity, good substrate scope, mild reaction conditions, and high efficiency. To the best of our knowledge, this is the first example of a regioselective C−H alkenylation of unprotected phenols utilizing phenolic hydroxyl group as a directing group. The alkenylation of unprotected tyrosine and intramolecular cyclization are also successfully carried out under this catalytic system in good yields. Furthermore, this novel method enables a late-stage modification of complex phenol-containing bioactive molecules toward a diversity-oriented drug discovery. 相似文献
11.
Huiying Zeng Zemin Wang Chao‐Jun Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(9):2885-2889
Transition metal catalyzed C?H functionalizations have been developed as powerful methods for C?C bond formations. Directing groups, removable directing groups, traceless directing groups, and transient directing groups (TDGs) have been successfully used to improve the reaction efficiencies. For the development of greener and more sustainable methods, C?H functionalization using a TDG that also serves as a reagent in aqueous solvent was investigated. The palladium‐catalyzed C?H functionalization of tryptamine derivatives using ketones in water successfully generated tetrahydro‐β‐carbolines with a quaternary carbon center at C1. Deuterium‐labeling experiments are discussed to provide insight into the mechanism. The C2‐position of pyridine was also successfully functionalized by this strategy. 相似文献
12.
Xiaodong Qiu Panpan Wang Dingyi Wang Minyan Wang Yu Yuan Zhuangzhi Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(5):1518-1522
Rhodium‐catalyzed C7‐selective decarbonylative arylation, olefination, and methylation of indoles with carboxylic acids or anhydrides by C?H and C?C bond activation have been developed. Furthermore, C7‐acylation products can also be generated selectively at a lower reaction temperature in the developed system. The key to the high reactivity and regioselectivity of this transformation is the appropriate choice of an indole N‐PtBu2 chelation‐assisted group. This method has many advantages, including easy access and removal of the directing group, the use of cheap and widely available coupling agents, no requirement of an external ligand or oxidant, a broad substrate scope, high efficiency, and the formation of a sole regioisomer. 相似文献
13.
Yan Zhang Julia Struwe Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2020,59(35):15076-15080
Metal‐catalyzed chelation‐assisted C?H olefinations have emerged as powerful tools for the construction of functionalized alkenes. Herein, we describe the rhoda‐electrocatalyzed C?H activation/alkenylation of arenes. The olefinations of challenging electron‐poor benzamides were thus accomplished in a fully dehydrogenative fashion under electrochemical conditions, avoiding stoichiometric chemical oxidants, and with H2 as the only byproduct. This versatile alkenylation reaction also features broad substrate scope and used electricity as a green oxidant. 相似文献
14.
Xiaodong Qiu Panpan Wang Dingyi Wang Minyan Wang Yu Yuan Zhuangzhi Shi 《Angewandte Chemie (International ed. in English)》2019,58(5):1504-1508
Rhodium‐catalyzed C7‐selective decarbonylative arylation, olefination, and methylation of indoles with carboxylic acids or anhydrides by C?H and C?C bond activation have been developed. Furthermore, C7‐acylation products can also be generated selectively at a lower reaction temperature in the developed system. The key to the high reactivity and regioselectivity of this transformation is the appropriate choice of an indole N‐PtBu2 chelation‐assisted group. This method has many advantages, including easy access and removal of the directing group, the use of cheap and widely available coupling agents, no requirement of an external ligand or oxidant, a broad substrate scope, high efficiency, and the formation of a sole regioisomer. 相似文献
15.
Rhodium(III)‐Catalyzed [3+2] Annulation of 5‐Aryl‐2,3‐dihydro‐1H‐pyrroles with Internal Alkynes through C(sp2)H/Alkene Functionalization
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Ming‐Bo Zhou Rui Pi Ming Hu Yuan Yang Ren‐Jie Song Dr. Yuanzhi Xia Prof. Dr. Jin‐Heng Li 《Angewandte Chemie (International ed. in English)》2014,53(42):11338-11341
This study describes a new rhodium(III)‐catalyzed [3+2] annulation of 5‐aryl‐2,3‐dihydro‐1H‐pyrroles with internal alkynes using a Cu(OAc)2 oxidant for building a spirocyclic ring system, which includes the functionalization of an aryl C(sp2)? H bond and addition/protonolysis of an alkene C?C bond. This method is applicable to a wide range of 5‐aryl‐2,3‐dihydro‐1H‐pyrroles and internal alkynes, and results in the assembly of the spiro[indene‐1,2′‐pyrrolidine] architectures in good yields with excellent regioselectivities. 相似文献
16.
Three‐component One‐pot Synthetic Route to Functionalized N‐Phenyl‐ and N,N‐(1,4‐phenylene)‐2‐alkylimino‐2,3‐dihydrothiazoles under Mild,Solvent‐ and Catalyst‐free Conditions
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A simple and efficient one‐pot synthesis of alkyl‐2‐(alkylimino)‐4‐methyl‐3‐phenyl‐2,3‐dihydrothiazole‐5‐carboxylate and dialkyl 3,3′‐(1,4‐phenylene)‐bis‐[2‐(alkylimino)‐4‐methyl‐2,3‐dihydrothiazole‐5‐carboxylate] derivatives from the reaction of phenylisothiocyanate (and also 1,4‐phenylene diisothiocyanate) and primary alkylamines in the presence of 2‐chloro‐1,3‐dicarbonyl compounds is described. This new protocol has several advantages such as lack of necessity of the catalyst and solvent, good yields,mild conditions and short times for reaction. 相似文献
17.
Rahul K. Shukla Akshay M. Nair Salman Khan Chandra M. R. Volla 《Angewandte Chemie (International ed. in English)》2020,59(39):17042-17048
An efficient Cp*CoIII‐catalyzed C8‐dienylation of quinoline‐N‐oxides was achieved by employing allenes bearing leaving groups at the α‐position as the dienylating agents. The reaction proceeds by CoIII‐catalyzed C?H activation of quinoline‐N‐oxides and regioselective migratory insertion of the allene followed by a β‐oxy elimination, leading to overall dienylation. Site‐selective C?H activation was achieved with excellent selectivity under mild reaction conditions, and 30 mol % of a NaF additive was found to be crucial for the efficient dienylation. The methodology features high stereoselectivity, mild reaction conditions, and good functional‐group tolerance. C8‐alkenylation of quinoline‐N‐oxides was achieved in the case of allenes devoid of leaving groups as coupling partners. Furthermore, gram‐scale preparation and preliminary mechanistic experiments were carried out to gain insights into the reaction mechanism. 相似文献
18.
Ruthenium(II)‐Catalyzed CH Functionalizations with Allenes: Versatile Allenylations and Allylations
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Sachiyo Nakanowatari Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):16246-16251
Ruthenium(II)‐catalyzed direct C?H functionalization of aromatic compounds with allenes was achieved under exceedingly mild reaction conditions to yield trisubstituted allenes. The reactions of N‐methoxybenzamides proceeded smoothly in an isohypsic fashion at ambient temperature with high chemo‐ and regioselectivity, thereby providing a versatile means of accessing trisubstituted allenes. Detailed mechanistic studies were suggestive of a kinetically relevant C?H metalation step, which occurs by the assistance of a carboxylate moiety; this also set the stage for unprecedented C?H allylations with removable directing groups in a step‐economical fashion. 相似文献
19.
Palladium‐Catalyzed Arylation of Unactivated γ‐Methylene C(sp3)H and δ‐CH Bonds with an Oxazoline‐Carboxylate Auxiliary
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Peng‐Xiang Ling Sheng‐Long Fang Xue‐Song Yin Kai Chen Bo‐Zheng Sun Prof. Dr. Bing‐Feng Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17503-17507
A palladium‐catalyzed arylation of unactivated γ‐methylene C(sp3)?H and remote δ‐C?H bonds by using an oxazoline‐carboxylate directing group has been developed. Arylation occurs with a broad substrate scope and high tolerance of functional groups (i.e., halogen, nitro, cyano, ether, trifluoromethyl, amine, and ester). The oxazoline‐type auxiliary can be removed under acidic conditions. 相似文献
20.
Transition‐metal‐catalyzed Chelation‐assisted C–H Functionalization of Aromatic Substrates
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In the past decade, transition‐metal‐catalyzed C–H activations have been very popular in the research field of organometallic chemistry, and have been considered as efficient and convenient strategies to afford complex natural products, functional advanced materials, fluorescent compounds, and pharmaceutical compounds. In this account, we begin with a brief introduction to the development of transition‐metal‐catalyzed C–H activation, especially the development of transition‐metal‐catalyzed chelation‐assisted C–H activation. Then, a more detailed discussion is directed towards our recent studies on the transition‐metal‐catalyzed chelation‐assisted oxidative C–H/C–H functionalization of aromatic substrates bearing directing functional groups. 相似文献