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1.
Rhodium‐Catalyzed Annulative Coupling of 3‐Phenylthiophenes with Alkynes Involving Double C‐H Bond Cleavages 下载免费PDF全文
Tomonori Iitsuka Dr. Koji Hirano Prof. Dr. Tetsuya Satoh Prof. Dr. Masahiro Miura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):385-389
Double C?H bond activation took place efficiently upon treatment of 3‐phenylthiophenes with alkynes in the presence of a rhodium catalyst and a copper salt oxidant to form the corresponding naphthothiophene derivatives. Dehydrogenative coupling with alkenes was also found to occur on the phenyl moiety rather than the thiophene ring. These reactions provide straightforward synthetic methods for π‐conjugated molecules involving a thiophene unit from readily available, simple building blocks. 相似文献
2.
Copper‐Catalyzed α‐Amination of Phosphonates and Phosphine Oxides: A Direct Approach to α‐Amino Phosphonic Acids and Derivatives 下载免费PDF全文
Stacey L. McDonald Prof. Dr. Qiu Wang 《Angewandte Chemie (International ed. in English)》2014,53(7):1867-1871
A direct approach to important α‐amino phosphonic acids and its derivatives has been developed by using copper‐catalyzed electrophilic amination of α‐phosphonate zincates with O‐acyl hydroxylamines. This amination provides the first example of C? N bond formation which directly introduces acyclic and cyclic amines to the α‐position of phosphonates in one step. The reaction is readily promoted at room temperature with as little as 0.5 mol % of catalyst, and demonstrates high efficiency on a broad substrate scope. 相似文献
3.
Stacey L. McDonald Charles E. Hendrick Prof. Dr. Qiu Wang 《Angewandte Chemie (International ed. in English)》2014,53(18):4667-4670
Direct amination of heteroarenes and arenes has been achieved in a one‐pot C? H zincation/copper‐catalyzed electrophilic amination procedure. This amination method provides an efficient and rapid approach to access a diverse range of heteroaromatic and aromatic amines including those previously inaccessible using C? H amination methods. The mild reaction conditions and good functional‐group compatibility demonstrate its great potential for the synthesis of important and complex amines. 相似文献
4.
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
5.
PdII‐Catalyzed Mild CH ortho Arylation and Intramolecular Amination Oriented by a Phosphinamide Group 下载免费PDF全文
Jing Guan Guo‐Jie Wu Dr. Fu‐She Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3301-3305
A novel protocol for the Pd‐catalyzed ortho‐arylation of aryl phosphinamide with boronic acid is reported. By using phosphinamide as a new directing group, the reaction proceeds efficiently under mild conditions at 40 °C. Mechanistic studies reveal that the reaction proceeds via a PdII to Pd0 cycle. The phosphinamide group is also shown to be an effective orienting group for direct C?H amination. 相似文献
6.
A Bioinspired Catalytic Aerobic Oxidative CH Functionalization of Primary Aliphatic Amines: Synthesis of 1,2‐Disubstituted Benzimidazoles 下载免费PDF全文
Khac Minh Huy Nguyen Dr. Martine Largeron 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(36):12606-12610
Aerobic oxidative C?H functionalization of primary aliphatic amines has been accomplished with a biomimetic cooperative catalytic system to furnish 1,2‐disubstituted benzimidazoles that play an important role as drug discovery targets. This one‐pot atom‐economical multistep process, which proceeds under mild conditions, with ambient air and equimolar amounts of each coupling partner, constitutes a convenient environmentally friendly strategy to functionalize non‐activated aliphatic amines that remain challenging substrates for non‐enzymatic catalytic aerobic systems. 相似文献
7.
Fen Wang Xinzhang Yu Zisong Qi Prof. Dr. Xingwei Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(2):511-516
Rhodium‐catalyzed sulfonylation, thioetherification, thiocyanation, and other heterofunctionalizations of arenes bearing a heterocyclic directing group have been realized. The reaction proceeds by initial RhIII‐catalyzed C?H hyperiodination of arene at room temperature followed by uncatalyzed nucleophilic functionalization. A diaryliodonium salt is isolated as an intermediate, which represents umpolung of the arene substrate, in contrast to previous studies that suggested umpolung of the coupling partner. 相似文献
8.
Dr. Shubhankar Kumar Bose Andrea Deißenberger Antonius Eichhorn Prof. Dr. Patrick G. Steel Prof. Dr. Zhenyang Lin Prof. Dr. Todd B. Marder 《Angewandte Chemie (International ed. in English)》2015,54(40):11843-11847
A zinc‐catalyzed combined C? X and C? H borylation of aryl halides using B2pin2 (pin=OCMe2CMe2O) to produce the corresponding 1,2‐diborylarenes under mild conditions was developed. Catalytic C? H bond activation occurs ortho to the halide groups if such a site is available or meta to the halide if the ortho position is already substituted. This method thus represents a novel use of a group XII catalyst for C? H borylation. This transformation does not proceed via a free aryne intermediate, but a radical process seems to be involved. 相似文献
9.
Catalytic 1,4‐Rhodium(III) Migration Enables 1,3‐Enynes to Function as One‐Carbon Oxidative Annulation Partners in CH Functionalizations 下载免费PDF全文
Dr. David J. Burns Prof. Hon Wai Lam 《Angewandte Chemie (International ed. in English)》2014,53(37):9931-9935
1,3‐Enynes containing allylic hydrogens cis to the alkyne are shown to act as one‐carbon partners, rather than two‐carbon partners, in various rhodium‐catalyzed oxidative annulations. The mechanism of these unexpected transformations is proposed to occur through double C? H activation, involving a hitherto rare example of the 1,4‐migration of a RhIII species. This phenomenon is general across a variety of substrates, and provides a diverse range of heterocyclic products. 相似文献
10.
Dr. Nicolas Gigant Dr. Laëtitia Chausset‐Boissarie Prof. Dr. Isabelle Gillaizeau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(25):7548-7564
Enamides are stable enamine surrogates and provide key intermediates for the synthesis of small but complex nitrogen‐containing compounds. Metal‐catalyzed regioselective functionalization of enamides provides a rapid method to synthesize useful nitrogen containing heterocycles. This review discloses the recent progress made in the development of the C?H functionalization of enamides involving efficient and atom‐economical routes. Syntheses of different heterocycles are classified based on the site reactivity of enamides and key mechanistic insights are given for each transformation. 相似文献
11.
Electrochemical Intramolecular CH Amination: Synthesis of Benzoxazoles and Benzothiazoles 下载免费PDF全文
Tatsuya Morofuji Dr. Akihiro Shimizu Prof. Dr. Jun‐ichi Yoshida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3211-3214
A new method for metal‐free intramolecular C?H amination has been developed. Electrochemical oxidation of 2‐pyrimidyloxybenzenes and 2‐pyrimidylthiobenzenes, which can be easily prepared from phenols and thiophenols, respectively, followed by the treatment of the resulting pyrimidinium ions with piperidine gives 2‐aminobenzoxazoles and 2‐aminobenzothiazoles, respectively. 相似文献
12.
Iron‐Catalyzed CαH Oxidation of Tertiary,Aliphatic Amines to Amides under Mild Conditions 下载免费PDF全文
Christopher J. Legacy Anqi Wang Brian J. O'Day Prof. Marion H. Emmert 《Angewandte Chemie (International ed. in English)》2015,54(49):14907-14910
De novo syntheses of amides often generate stoichiometric amounts of waste. Thus, recent progress in the field has focused on precious metal catalyzed, oxidative protocols to generate such functionalities. However, simple tertiary alkyl amines cannot be used as starting materials in these protocols. The research described herein enables the oxidative synthesis of amides from simple, noncyclic tertiary alkyl amines under synthetically useful, mild conditions through a biologically inspired approach: Fe‐catalyzed Cα? H functionalization. Mechanistic investigations provide insight into reaction intermediates and allow the development of a mild Cα? H cyanation method using the same catalyst system. The protocol was further applied to oxidize the drug Lidocaine, demonstrating the potential utility of the developed chemistry for metabolite synthesis. 相似文献
13.
Palladium‐Catalyzed Construction of Heteroatom‐Containing π‐Conjugated Systems by Intramolecular Oxidative CH/CH Coupling Reaction 下载免费PDF全文
Kenta Saito Dr. Prasanna Kumara Chikkade Prof. Dr. Motomu Kanai Prof. Dr. Yoichiro Kuninobu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(23):8365-8368
Synthesis of heteroatom‐containing ladder‐type π‐conjugated molecules was successfully achieved via a palladium‐catalyzed intramolecular oxidative C?H/C?H cross‐coupling reaction. This reaction provides a variety of π‐conjugated molecules bearing heteroatoms, such as nitrogen, oxygen, phosphorus, and sulfur atoms, and a carbonyl group. The π‐conjugated molecules were synthesized efficiently, even in gram scale, and larger π‐conjugated molecules were also obtained by a double C?H/C?H cross‐coupling reaction and successive oxidative cycloaromatization. 相似文献
14.
Organomagnesium‐Catalyzed Isomerization of Terminal Alkynes to Allenes and Internal Alkynes 下载免费PDF全文
Dr. Raphaël Rochat Koji Yamamoto Michael J. Lopez Haruki Nagae Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8112-8120
Organomagnesium complexes 2 were synthesized from N,N‐dialkylamineimine ligands 1 and dibenzylmagnesium by benzylation of the imine moiety. 3‐Aryl‐1‐propynes reacted with 2 to form the corresponding tetraalkynyl complexes, which acted as catalysts for the transformation of these terminal alkynes into allenes and further to internal alkynes under mild conditions. To the best of our knowledge, this example is the first of an organomagnesium‐catalyzed isomerization of alkynes. Notably, the reactions proceeded through temporally separated autotandem catalysis, thus allowing the isolation of the allene or internal alkyne species in good yields. Mechanistic experiments suggested that the catalytically active tetraalkynyl complexes consist of a tautomeric mixture of alkynyl‐, allenyl‐, and propargylmagnesium species. 相似文献
15.
A Convenient Synthesis of N‐Aryl Benzamides by Rhodium‐Catalyzed ortho‐Amidation and Decarboxylation of Benzoic Acids 下载免费PDF全文
Dr. Xian‐Ying Shi Ke‐Yan Liu Juan Fan Xue‐Fen Dong Prof. Dr. Jun‐Fa Wei Prof. Dr. Chao‐Jun Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):1900-1903
The rhodium‐catalyzed amidation of substituted benzoic acids with isocyanates by directed C?H functionalization followed by decarboxylation to afford the corresponding N‐aryl benzamides is demonstrated, in which the carboxylate serves as a unique, removable directing group. Notably, less common meta‐substituted N‐aryl benzamides are generated readily from more accessible para‐ or ortho‐substituted groups by employing this strategy. 相似文献
16.
Regioselective C3 Alkenylation of 4 H‐pyrido[1,2‐a]pyrimidin‐4‐ones via Palladium‐Catalyzed CH Activation 下载免费PDF全文
Dr. Wenjie Liu Dr. Shaohua Wang Qi Zhang Jingwen Yu Jiahe Li Zhiwei Xie Prof. Hua Cao 《化学:亚洲杂志》2014,9(9):2436-2439
A general and efficient palladium‐catalyzed direct C3 alkenylation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones using AgOAc/O2 as the oxidant has been developed. A variety of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones were successfully coupled with acrylate esters, styrenes, methylvinylketone, and acrylamide in moderate to excellent yields. The reaction exhibited complete regio‐ and stereoselectivity. This transformation provides an attractive new approach to functionalize 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones. 相似文献
17.
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
18.
Ai‐Hua Zhou Fei Pan Dr. Chunyin Zhu Prof. Dr. Long‐Wu Ye 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10278-10288
Fluorenes are a commonly encountered structural motif in materials science, pharmaceutical chemistry, and organic synthesis. Among various strategies towards the synthesis of this unique structure, transition metal‐catalyzed functionalization has emerged as one of the most efficient methods. This Minireview presents an overview of the recent advances in this emerging area by highlighting the reactions’ specificity and applicability and, where possible, provides a mechanistic rationale. 相似文献
19.
Ruthenium–Porphyrin‐Catalyzed Diastereoselective Intramolecular Alkyl Carbene Insertion into CH Bonds of Alkyl Diazomethanes Generated In Situ from N‐Tosylhydrazones 下载免费PDF全文
Zhen Guo Jinhu Wei Prof. Dr. Chi‐Ming Che 《Angewandte Chemie (International ed. in English)》2014,53(51):14175-14180
With a ruthenium–porphyrin catalyst, alkyl diazomethanes generated in situ from N‐tosylhydrazones efficiently underwent intramolecular C(sp3)? H insertion of an alkyl carbene to give substituted tetrahydrofurans and pyrrolidines in up to 99 % yield and with up to 99:1 cis selectivity. The reaction displays good tolerance of many functionalities, and the procedure is simple without the need for slow addition with a syringe pump. From a synthetic point of view, the C? H insertion of N‐tosylhydrazones can be viewed as reductive coupling between a C?O bond and a C? H bond to form a new C? C bond, since N‐tosylhydrazones can be readily prepared from carbonyl compounds. This reaction was successfully applied in a concise synthesis of (±)‐pseudoheliotridane. 相似文献
20.
Heterogeneously Porous γ‐MnO2‐Catalyzed Direct Oxidative Amination of Benzoxazole through CH Activation in the Presence of O2 下载免费PDF全文
Provas Pal Arnab Kanti Giri Harshvardhan Singh Dr. Subhash Chandra Ghosh Dr. Asit Baran Panda 《化学:亚洲杂志》2014,9(9):2392-2396
Oxidative amination of azoles through catalytic C? H bond activation is a very important reaction due to the presence of 2‐aminoazoles in several biologically active compounds. However, most of the reported methods are performed under homogeneous reaction conditions using excess reagents and additives. Herein, we report the heterogeneous, porous γ‐MnO2‐catalyzed direct amination of benzoxazole with wide range of primary and secondary amines. The amination was carried under mild reaction conditions and using molecular oxygen as a green oxidant, without any additives. The catalyst can easily be separated by filtration and reused several times without a significant loss of its catalytic performance. Of note, the reaction tolerates a functional group such as alcohol, thus indicating the broad applicability of this reaction. 相似文献