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1.
Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation,Hydrogen Atom Transfer,and Carbene/Nitrene Transfer 下载免费PDF全文
John C. K. Chu Prof. Tomislav Rovis 《Angewandte Chemie (International ed. in English)》2018,57(1):62-101
The functionalization of C(sp3)?H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C?H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C?H activation, 1,n‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp3)?H bonds. For each strategy, the scope, the reactivity of different C?H bonds, the position of the reacting C?H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C?H functionalization reactions and inspire future research in this area. 相似文献
2.
Palladium‐Catalyzed γ‐C(sp3)−H Arylation of Thiols by a Detachable Protecting/Directing Group 下载免费PDF全文
Likun Jin Jianchun Wang Prof. Dr. Guangbin Dong 《Angewandte Chemie (International ed. in English)》2018,57(38):12352-12355
Reported herein is a palladium‐catalyzed, directed γ‐C(sp3)?H arylation of protected thiols. The key is to utilize Michael acceptors as a dual reagent to install a protecting/directing group on thiols by a thiol‐Michael click reaction, and remove it later under basic conditions. The C?H arylation proceeds with high functional‐group tolerance and the deprotected thiols can be further transformed into other sulfur‐containing compounds. This unique mode of activation could open the door for site‐selective functionalization of thiols or other sulfur‐containing compounds at unactivated positions. 相似文献
3.
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
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.
Rhodium(III)‐Catalyzed Alkenylation–Annulation of closo‐Dodecaborate Anions through Double B−H Activation at Room Temperature 下载免费PDF全文
Yuanbin Zhang Yuji Sun Furong Lin Jiyong Liu Dr. Simon Duttwyler 《Angewandte Chemie (International ed. in English)》2016,55(50):15609-15614
1,2,3‐Trisubstituted closo‐dodecaborates with B?O, B?N, and B?C bonds as well as a fused borane oxazole ring have been synthesized by rhodium‐catalyzed direct cage B?H alkenylation and annulation of ureido boranes in the first reported example of regioselective B?H bond functionalization of the [B12H12]2? cage by transition‐metal catalysis. This reaction proceeded at room temperature under ambient conditions and exhibited excellent selectivity for efficient monoalkenylation with good functional‐group tolerance. The urea moiety enabled B?H activation by acting as a directing group, was incorporated in the oxazole ring in situ, and also avoided multiple alkenylation. A possible mechanism is proposed on the basis of the isolation of a rhodium agostic intermediate and control experiments. 相似文献
6.
Li‐Jun Xiao Kai Hong Fan Luo Liang Hu William R. Ewing Kap‐Sun Yeung Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2020,59(24):9594-9600
The use of chiral transient directing groups (TDGs) is a promising approach for developing PdII‐catalyzed enantioselective C(sp3)?H activation reactions. However, this strategy is challenging because the stereogenic center on the TDG is often far from the C?H bond, and both TDG covalently attached to the substrate and free TDG are capable of coordinating to PdII centers, which can result in a mixture of reactive complexes. We report a PdII‐catalyzed enantioselective β‐C(sp3)?H arylation reaction of aliphatic ketones using a chiral TDG. A chiral trisubstituted cyclobutane was efficiently synthesized from a mono‐substituted cyclobutane through sequential C?H arylation reactions, thus demonstrating the utility of this method for accessing structurally complex products from simple starting materials. The use of an electron‐deficient pyridone ligand is crucial for the observed enantioselectivity. Interestingly, employing different silver salts can reverse the enantioselectivity. 相似文献
7.
《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
8.
Dr. Xuesong Wu Yan Zhao Prof. Dr. Haibo Ge 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(31):9530-9533
Intramolecular dehydrogenative cyclization of aliphatic amides was achieved on unactivated sp3 carbon atoms by a nickel‐catalyzed C?H bond functionalization process with the assistance of a bidentate directing group. The reaction favors the C?H bonds of β‐methyl groups over the γ‐methyl or β‐methylene groups. Additionally, a predominant preference for the β‐methyl C?H bonds over the aromatic sp2 C?H bonds was observed. Moreover, this process also allows for the effective functionalization of benzylic secondary sp3 C?H bonds. 相似文献
9.
A rhodium(III)‐catalyzed redox‐neutral coupling of α‐trifluoromethylacrylic acid with bezamides proceeds smoothly accompanied by amide‐directed C?H bond cleavage to produce β‐[2‐(aminocarbonyl)phenyl]‐α‐trifluoromethylpropanoic acid derivatives. One of the products can be transformed to a trifluoromethyl substituted heterocyclic compound. In addition, the redox‐neutral coupling of α‐trifluoromethylacrylic acid with related aromatic substrates possessing a nitrogen‐containing directing group can also be conducted under similar conditions. 相似文献
10.
Thioketone‐Directed Palladium(II)‐Catalyzed C−H Arylation of Ferrocenes with Aryl Boronic Acids 下载免费PDF全文
Zhong‐Jian Cai Chen‐Xu Liu Dr. Qing Gu Prof. Dr. Shu‐Li You 《Angewandte Chemie (International ed. in English)》2018,57(5):1296-1299
A palladium(II)‐catalyzed thioketone‐chelation‐assisted direct C?H arylation of ferrocenes is described. With thioketone as an efficient directing group, various monoaryl‐ and diaryl‐substituted thiocarbonylferrocenes were obtained by palladium‐catalyzed direct C?H functionalization in high yields under mild and base‐free reaction conditions. Furthermore, the arylated thiocarbonylferrocene could undergo diverse transformations. 相似文献
11.
Transition Metal‐Catalyzed Carbonylative CH Bond Functionalization of Arenes and C(sp3)H Bond of Alkanes 下载免费PDF全文
Sandip T. Gadge Prashant Gautam Bhalchandra M. Bhanage 《Chemical record (New York, N.Y.)》2016,16(2):835-856
In this article, we present the progress made in the area of carbonylative C? H functionalization, with special emphasis on arenes and alkanes. The importance of directing group assistance and C? H functionalization using CO surrogates is also included. The budding development in the area of transition metal‐catalyzed C(sp3)? H activation makes us feel it necessary to file a summary on the past, as well as current, contributions and a prospective outlook on the transition metal‐catalyzed carbonylative transformation of C? H bonds, which is the focus of this review. 相似文献
12.
Ashish A. Mishra Dnyaneshwar Subhedar Bhalchandra M. Bhanage 《Chemical record (New York, N.Y.)》2019,19(9):1829-1857
This review represents nickel, cobalt and palladium catalyzed C?H activation of sp3 carbon, with special emphasis on methyl C?H activation. The importance of directing group assistance and effect of ligand on β‐ or γ‐ C(sp3)?H activation is summarized in this review. The mechanistic study for Ni, Co and Pd catalyzed sp3 C?H bond functionalization also discussed in detail. 相似文献
13.
Julia Pedroni Michele Boghi Dr. Tanguy Saget Prof. Dr. Nicolai Cramer 《Angewandte Chemie (International ed. in English)》2014,53(34):9064-9067
β‐Lactams are very important structural motifs because of their broad biological activities as well as their propensity to engage in ring‐opening reactions. Transition‐metal‐catalyzed C? H functionalizations have emerged as strategy enabling yet uncommon highly efficient disconnections. In contrast to the significant progress of Pd0‐catalyzed C? H functionalization for aryl–aryl couplings, related reactions involving the formation of saturated C(sp3)? C(sp3) bonds are elusive. Reported here is an asymmetric C? H functionalization approach to β‐lactams using readily accessible chloroacetamide substrates. Important aspects of this transformation are challenging C(sp3)? C(sp3) and strain‐building reductive eliminations to for the four‐membered ring. In general, the β‐lactams are formed in excellent yields and enantioselectivities using a bulky taddol phosphoramidite ligand in combination with adamantyl carboxylic acid as cocatalyst. 相似文献
14.
Mgane Valero Thomas Kruissink Jennifer Blass Remo Weck Stefan Güssregen Alleyn T. Plowright Volker Derdau 《Angewandte Chemie (International ed. in English)》2020,59(14):5626-5631
An assessment of the C?H activation catalyst [(COD)Ir(IMes)(PPh3)]PF6 (COD=1,5‐cyclooctadiene, IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazol‐2‐ylidene) in the deuteration of phenyl rings containing different functional directing groups is divulged. Competition experiments have revealed a clear order of the directing groups in the hydrogen isotope exchange (HIE) with an iridium (I) catalyst. Through DFT calculations the iridium–substrate coordination complex has been identified to be the main trigger for reactivity and selectivity in the competition situation with two or more directing groups. We postulate that the competition concept found in this HIE reaction can be used to explain regioselectivities in other transition‐metal‐catalyzed functionalization reactions of complex drug‐type molecules as long as a C?H activation mechanism is involved. 相似文献
15.
Divergent Syntheses of Fused β‐Naphthol and Indene Scaffolds by Rhodium‐Catalyzed Direct and Decarbonylative Alkyne–Benzocyclobutenone Couplings 下载免费PDF全文
Peng‐hao Chen Dr. Tao Xu Prof. Dr. Guangbin Dong 《Angewandte Chemie (International ed. in English)》2014,53(6):1674-1678
A tunable rhodium‐catalyzed intramolecular alkyne insertion reaction proceeding through the C? C cleavage of benzocyclobutenones is described. Selective formation of either the direct or decarbonylative insertion product can be controlled by using different catalytic systems. A variety of fused β‐naphthol and indene scaffolds were obtained in good yields with high functional group tolerance. This work illustrates a divergent approach to synthesize fused‐ring systems by C? C activation/functionalization. 相似文献
16.
Diaryliodoniums by Rhodium(III)‐Catalyzed CH Activation: Mild Synthesis and Diversified Functionalizations 下载免费PDF全文
Dr. Fang Xie Zhipeng Zhang Dr. Xinzhang Yu Guodong Tang Prof. Dr. Xingwei Li 《Angewandte Chemie (International ed. in English)》2015,54(25):7405-7409
Diaryliodonium salts play an increasingly important role as an aryl source. Reported is the first synthesis of diaryliodoniums by rhodium(III)‐catalyzed C? H hyperiodination of electron‐poor arenes under chelation assistance. This C? I coupling reaction occurred at room temperature with high regio‐selectivity and functional‐group compatibility. Subsequent diversified nucleophilic functionalization of a diaryliodonium allowed facile construction of C? C, C? N, C? O, C? S, C? P and C? Br bonds, and in all cases the initial functionalization occurred at the arene containing the chelating‐group. 相似文献
17.
Steric Effect of Carboxylate Ligands on Pd‐Catalyzed Intramolecular C(sp2)–H and C(sp3)–H Arylation Reactions 下载免费PDF全文
Yutaka Tanji Naoya Mitsutake Prof. Dr. Tetsuaki Fujihara Prof. Dr. Yasushi Tsuji 《Angewandte Chemie (International ed. in English)》2018,57(32):10314-10317
A bulky carboxylic acid bearing three cyclohexylmethyl substituents at the α‐position, namely, tri(cyclohexylmethyl)acetic acid, is demonstrated to act as an efficient ligand source in Pd‐catalyzed intramolecular C(sp2)?H and C(sp3)?H arylation reactions. The reactions proceed smoothly under mild reaction conditions, even at room temperature due to the steric bulk of the carboxylate ligands, which accelerates the rate‐determining C?H bond activation step in the catalytic cycle. 相似文献
18.
Manganese(I)‐Catalyzed C−H Activation: The Key Role of a 7‐Membered Manganacycle in H‐Transfer and Reductive Elimination 下载免费PDF全文
Dr. Nasiru P. Yahaya Kate M. Appleby Magdalene Teh Conrad Wagner Erik Troschke Joshua T. W. Bray Prof. Simon B. Duckett L. Anders Hammarback Dr. Jonathan S. Ward Jessica Milani Dr. Natalie E. Pridmore Dr. Adrian C. Whitwood Dr. Jason M. Lynam Prof. Ian J. S. Fairlamb 《Angewandte Chemie (International ed. in English)》2016,55(40):12455-12459
Manganese‐catalyzed C?H bond activation chemistry is emerging as a powerful and complementary method for molecular functionalization. A highly reactive seven‐membered MnI intermediate is detected and characterized that is effective for H‐transfer or reductive elimination to deliver alkenylated or pyridinium products, respectively. The two pathways are determined at MnI by judicious choice of an electron‐deficient 2‐pyrone substrate containing a 2‐pyridyl directing group, which undergoes regioselective C?H bond activation, serving as a valuable system for probing the mechanistic features of Mn C?H bond activation chemistry. 相似文献
19.
Chase A. Salazar Joseph J. Gair Kaylin N. Flesch Ilia A. Guzei Jared C. Lewis Shannon S. Stahl 《Angewandte Chemie (International ed. in English)》2020,59(27):10873-10877
Mono‐N‐protected amino acids (MPAAs) are increasingly common ligands in Pd‐catalyzed C?H functionalization reactions. Previous studies have shown how these ligands accelerate catalytic turnover by facilitating the C?H activation step. Here, it is shown that MPAA ligands exhibit a second property commonly associated with ligand‐accelerated catalysis: the ability to support catalytic turnover at substoichiometric ligand‐to‐metal ratios. This catalytic role of the MPAA ligand is characterized in stoichiometric C?H activation and catalytic C?H functionalization reactions. Palladacycle formation with substrates bearing carboxylate and pyridine directing groups exhibit a 50–100‐fold increase in rate when only 0.05 equivalents of MPAA are present relative to PdII. These and other mechanistic data indicate that facile exchange between MPAAs and anionic ligands coordinated to PdII enables a single MPAA to support C?H activation at multiple PdII centers. 相似文献
20.
Enantiopure Sulfinyl Aniline as a Removable and Recyclable Chiral Auxiliary for Asymmetric C(sp3)−H Bond Activation 下载免费PDF全文
Soufyan Jerhaoui Dr. Faouzi Chahdoura Clémence Rose Dr. Jean‐Pierre Djukic Dr. Joanna Wencel‐Delord Prof. Françoise Colobert 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17397-17406
An original and recyclable chiral bidentate aniline‐sulfoxide‐based directing group has been developed. This auxiliary allows challenging stereoselective Pd‐catalyzed direct functionalization of small cycloalkanes through C–aryl and C–alkyl bond formation. Although moderate diastereoselectivities are observed, both optically pure enantiomers of the highly functionalized products can be obtained separately by simple silica gel chromatography and cleavage of the chiral auxiliary. This strategy was further applied to the preparation of enantiomerically pure 1,2,3‐trisubstituted cyclopropane carboxylic acid derivatives, with three stereogenic centers and bearing both alkyl and aromatic substituents. These molecular scaffolds are not yet reported in the literature. The synthetic utility of this approach is validated by the chiral auxiliary being readily cleaved and recovered posteriori to the C?H activation step, without deterioration of its optical purity. Finally, an unprecedented palladacycle intermediate generated through C?H activation of the cyclopropane moiety has been isolated and fully characterized. Initial DFT calculations shed additional light on the reactivity of this original intermediate. 相似文献