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1.
A Modified System for the Synthesis of Enantioenriched N‐Arylamines through Copper‐Catalyzed Hydroamination 下载免费PDF全文
Saki Ichikawa Dr. Shaolin Zhu Prof. Dr. Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2018,57(28):8714-8718
Despite significant recent progress in copper‐catalyzed enantioselective hydroamination chemistry, the synthesis of chiral N‐arylamines, which are frequently found in natural products and pharmaceuticals, has not been realized. Initial experiments with N‐arylhydroxylamine ester electrophiles were unsuccessful and, instead, their reduction in the presence of copper hydride (CuH) catalysts was observed. Herein, we report key modifications to our previously reported hydroamination methods that lead to broadly applicable conditions for the enantioselective net addition of secondary anilines across the double bond of styrenes, 1,1‐disubstituted olefins, and terminal alkenes. NMR studies suggest that suppression of the undesired reduction pathway is the basis for the dramatic improvements in yield under the reported method. 相似文献
2.
Stereodivergent Synthesis of N‐Heterocycles by Catalyst‐Controlled,Activity‐Directed Tandem Annulation of Diazo Compounds with Amino Alkynes 下载免费PDF全文
Kai Liu Chenghao Zhu Junxiang Min Dr. Shiyong Peng Guangyang Xu Prof. Dr. Jiangtao Sun 《Angewandte Chemie (International ed. in English)》2015,54(44):12962-12967
A stereodivergent synthesis of five‐membered N‐heterocycles, such as 2,3‐dihydropyrroles, and 2‐methylene and 3‐methylene pyrrolidines, has been developed through a tandem annulation of amino alkynes with diazo compounds and involves the trapping of in situ formed intermediates. Mechanistic investigations indicate that the copper‐catalyzed tandem annulations proceed by allenoate formation and subsequent intramolecular hydroamination. In contrast, the rhodium‐catalyzed protocol features a carbenoid insertion into the N? H bond and subsequent Conia‐ene cyclization. 相似文献
3.
Enantioselective Synthesis of α‐Aminosilanes by Copper‐Catalyzed Hydroamination of Vinylsilanes 下载免费PDF全文
Nootaree Niljianskul Dr. Shaolin Zhu Prof. Dr. Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2015,54(5):1638-1641
The synthesis of α‐aminosilanes by a highly enantio‐ and regioselective copper‐catalyzed hydroamination of vinylsilanes is reported. The system employs Cu‐DTBM‐SEGPHOS as the catalyst, diethoxymethylsilane as the stoichiometric reductant, and O‐benzoylhydroxylamines as the electrophilic nitrogen source. This hydroamination reaction is compatible with differentially substituted vinylsilanes, thus providing access to amino acid mimics and other valuable chiral organosilicon compounds. 相似文献
4.
Guangcan Xu Sbastien Leloux Pinglu Zhang Jorge Meijide Surez Yongmin Zhang Etienne Derat Mickaël Mnand Olivia Bistri‐Aslanoff Sylvain Roland Tom Leyssens Olivier Riant Matthieu Sollogoub 《Angewandte Chemie (International ed. in English)》2020,59(19):7591-7597
The encapsulation of copper inside a cyclodextrin capped with an N‐heterocyclic carbene (ICyD) allowed both to catch the elusive monomeric (L)CuH and a cavity‐controlled chemoselective copper‐catalyzed hydrosilylation of α,β‐unsaturated ketones. Remarkably, (α‐ICyD)CuCl promoted the 1,2‐addition exclusively, while (β‐ICyD)CuCl produced the fully reduced product. The chemoselectivity is controlled by the size of the cavity and weak interactions between the substrate and internal C?H bonds of the cyclodextrin. 相似文献
5.
A Copper‐Catalyzed Decarboxylative Amination/Hydroamination Sequence: Switchable Synthesis of Functionalized Indoles 下载免费PDF全文
Tian‐Ren Li Bei‐Yi Cheng Ya‐Ni Wang Mao‐Mao Zhang Prof. Dr. Liang‐Qiu Lu Prof. Dr. Wen‐Jing Xiao 《Angewandte Chemie (International ed. in English)》2016,55(40):12422-12426
A copper‐catalyzed decarboxylative amination/hydroamination sequence of propargylic carbamates with various nucleophiles is described for the first time. It features an earth‐abundant metal catalyst, mild reaction conditions, and high efficiency. Further treatments of the resultant key intermediates using an acid or a base in one pot enable the controllable and divergent synthesis of two types of functionalized indoles. Moreover, experiments to demonstrate the synthetic potential of this methodology are performed. 相似文献
6.
CuH‐Catalysed Hydroamination of Styrene with Hydroxylamine Esters: A Coupled Cluster Scrutiny of Mechanistic Pathways 下载免费PDF全文
Dr. Sven Tobisch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8290-8300
A detailed computational exploration of mechanistic intricacies of the copper(I) hydride (CuH)‐catalysed hydroamination of styrene with a prototype hydroxylamine ester by a recently reported [(dppbz)CuH] catalyst (dppbz≡{P^P}≡1,2‐bis(diphenylphosphino)‐benzene) is presented. A variety of plausible mechanistic avenues have been pursued by means of a sophisticated computational methodology, from which a general understanding of the factors controlling hydroamination catalysis emerged. The catalytically competent {P^P}CuI hydride, which is predominantly present as its dimer, involves in irreversible hydrocupration proceeding with complete 2,1 regioselectivity to form a secondary {P^P}CuI benzyl intermediate. Its interception with benzylamine ester produces the branched tertiary amine product and {P^P}CuI benzoate upon intramolecular SN2 disruption of the amine electrophile′s N?O linkage, to precede a highly rapid, strongly exergonic C?N bond‐forming reductive elimination. The {P^P}CuI benzoate corresponds to the catalyst resting state and its conversion back into the {P^P}CuI hydride upon transmetalation with a hydrosilane is turnover limiting. The effect of electronic perturbations at the amine electrophile upon the reaction rate for productive hydroamination catalysis and also non‐productive reduction of the hydroxylamine ester has been gauged, which unveiled a more fundamental insight into catalytic structure‐performance relationships. 相似文献
7.
Yujing Zhou Dr. Oliver D. Engl Dr. Jeffrey S. Bandar Emma D. Chant Prof. Dr. Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2018,57(22):6672-6675
A CuH‐catalyzed enantioselective hydroamidation reaction of vinylarenes has been developed using readily accessible 1,4,2‐dioxazol‐5‐ones as electrophilic amidating reagents. This method provides a straightforward and efficient approach to synthesize chiral amides in good yields with high levels of enantiopurity under mild conditions. Moreover, this transformation tolerates substrates bearing a broad range of functional groups. 相似文献
8.
Yahui Li Dr. Kaiwu Dong Fengxiang Zhu Zechao Wang Prof. Dr. Xiao‐Feng Wu 《Angewandte Chemie (International ed. in English)》2016,55(25):7227-7230
Carbonylation reactions are a most powerful method for the synthesis of carbonyl‐containing compounds. However, most known carbonylation procedures still require noble‐metal catalysts and the use of activated compounds and good nucleophiles as substrates. Herein, we developed a copper‐catalyzed carbonylative transformation of cycloalkanes and amides. Imides were prepared in good yields by carbonylation of a C(sp3)?H bond of the cycloalkane with the amides acting as weak nucleophiles. Notably, this is the first report of copper‐catalyzed carbonylative C?H activation. 相似文献
9.
Avijit Hazra Mitchell T. Lee Justin F. Chiu Prof. Gojko Lalic 《Angewandte Chemie (International ed. in English)》2018,57(19):5492-5496
We have developed a photoinduced copper‐catalyzed alkylation of terminal alkynes with primary, secondary, or tertiary alkyl iodides as electrophiles. The reaction has a broad substrate scope and can be successfully performed in the presence of ester, nitrile, aryl halide, ketone, sulfonamide, epoxide, alcohol, and amide functional groups. The alkylation is promoted by blue light (λ≈450 nm) and proceeds at room temperature in the absence of any additional metal catalysts. The use of a terpyridine ligand is essential for the success of the reaction and is shown to prevent photoinduced copper‐catalyzed polymerization of the starting materials. 相似文献
10.
Cu‐Catalyzed Hydroxymethylation of Unactivated Alkyl Iodides with CO To Provide One‐Carbon‐Extended Alcohols 下载免费PDF全文
We have developed a reductive carbonylation method by which unactivated alkyl iodides can be hydroxymethylated to provide one‐carbon‐extended alcohol products under Cu‐catalyzed conditions. The method is tolerant of alkyl β‐hydrogen atoms, is robust towards a wide variety of functional groups, and was applied to primary, secondary, and tertiary alkyl iodide substrates. Mechanistic experiments indicate that the transformation proceeds by atom‐transfer carbonylation (ATC) of the alkyl iodide followed in tandem by two CuH‐mediated reductions in rapid succession. This radical mechanism renders the Cu‐catalyzed system complementary to precious‐metal‐catalyzed reductive carbonylation reactions. 相似文献
11.
Copper‐Catalyzed Propargylic Substitution of Dichloro Substrates: Enantioselective Synthesis of Trisubstituted Allenes and Formation of Propargylic Quaternary Stereogenic Centers 下载免费PDF全文
Dr. Hailing Li Dr. David Grassi Dr. Laure Guénée Prof. Dr. Thomas Bürgi Prof. Dr. Alexandre Alexakis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16694-16706
An easy and versatile Cu‐catalyzed propargylic substitution process is presented. Using easily prepared prochiral dichloro substrates, readily available Grignard reagents together with catalytic amount of copper salt and chiral ligand, we accessed a range of synthetically interesting trisubstituted chloroallenes. Substrate scope and nucleophile scope are broad, providing generally high enantioselectivity for the desired 1,3‐substitution products. The enantioenriched chloroallenes could be further transformed into the corresponding trisubstituted allenes or terminal alkynes bearing all‐carbon quaternary stereogenic centers, through the copper‐catalyzed enantiospecific 1,1/1,3‐substitutions. The two successive copper‐catalyzed reactions could be eventually combined into a one‐pot procedure and different desired allenes or alkynes were obtained respectively with high enantiomeric excesses. 相似文献
12.
Xi‐Jie Dai Oliver D. Engl Thierry Len Stephen L. Buchwald 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3445-3449
Herein, we report a practical two‐step synthetic route to α‐arylpyrrolidines through Suzuki–Miyaura cross‐coupling and enantioselective copper‐catalyzed intramolecular hydroamination reactions. The excellent stereoselectivity and broad scope for the transformation of substrates with pharmaceutically relevant heteroarenes render this method a practical and versatile approach for pyrrolidine synthesis. Additionally, this intramolecular hydroamination strategy facilitates the asymmetric synthesis of tetrahydroisoquinolines and medium‐ring dibenzo‐fused nitrogen heterocycles. 相似文献
13.
Kai Liu Chenghao Zhu Junxiang Min Shiyong Peng Guangyang Xu Jiangtao Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(44):13154-13159
A stereodivergent synthesis of five‐membered N‐heterocycles, such as 2,3‐dihydropyrroles, and 2‐methylene and 3‐methylene pyrrolidines, has been developed through a tandem annulation of amino alkynes with diazo compounds and involves the trapping of in situ formed intermediates. Mechanistic investigations indicate that the copper‐catalyzed tandem annulations proceed by allenoate formation and subsequent intramolecular hydroamination. In contrast, the rhodium‐catalyzed protocol features a carbenoid insertion into the N H bond and subsequent Conia‐ene cyclization. 相似文献
14.
Andreas Weickgenannt Dipl.‐Chem. Martin Oestreich Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(2):402-412
Silicon‐ and tin‐containing molecules are versatile building blocks in organic synthesis. A stalwart method for their preparation relies on the stoichiometric use of silicon‐ and tin‐based cuprates, although a few copper(I)‐catalyzed or even copper‐free protocols have been known for decades. In this Concept, we describe our efforts towards copper(I)‐catalyzed carbon? silicon and also carbon? tin bond formations using soft bis(triorganosilyl) and bis(triorganostannyl) zinc reagents as powerful sources of nucleophilic silicon and tin. Conjugate addition, allylic substitution, and carbon? carbon multiple bond functionalization is now catalytic in copper! 相似文献
15.
Copper‐Catalyzed Synthesis of 1,1‐Diborylalkanes through Regioselective Dihydroboration of Terminal Alkynes 下载免费PDF全文
The copper‐catalyzed sequential hydroboration of terminal alkynes with pinacolborane to prepare 1,1‐diborylalkanes directly from alkynes was studied. Protected propargyl amines, propargyl alcohol derivatives, and simple alkynes regioselectively produced the desired 1,1‐diborylalkanes in good yields with a copper/xantphos catalyst. 相似文献
16.
Dr. Chih‐Ming Chou Dr. Joyram Guin Dr. Christian Mück‐Lichtenfeld Prof. Dr. Stefan Grimme Prof. Dr. Armido Studer 《化学:亚洲杂志》2011,6(5):1197-1209
An efficient synthesis of N‐phthalimidyl, benzamidyl, acetamidyl, carbamoyl, and ureayl derivatives of dihydropyridines and the application of these reagents as precursors for N‐centered radicals are presented. These aminated dihydropyridines could be used in radical‐transfer hydroamination reactions of various electron‐rich as well as nonactivated olefins in the presence of thiols as polarity‐reversal catalysts. These reactions worked without the aid of any transition metal. Steric and electronic effects exerted by the N‐substitutents of the N‐centered radicals are discussed. In contrast to most metal‐catalyzed processes, the radical hydroamination delivered the opposite regioisomer with excellent anti‐Markovnikov selectivity. Hydroamination products were obtained as protected amines that are readily isolated. 相似文献
17.
The asymmetric formal hydroamination of enamines using a CuH catalyst is reported. The method provides a straightforward and efficient approach to the synthesis of chiral 1,2‐dialkyl amines in good yields with high levels of enantioselectivities for a broad range of substrates, and should have significant value for the preparation of molecules bearing a 1,2‐diamine motif. 相似文献
18.
A Copper Catalyst with a Cinchona‐Alkaloid‐Based Sulfonamide Ligand for Asymmetric Radical Oxytrifluoromethylation of Alkenyl Oximes 下载免费PDF全文
Dr. Xi‐Tao Li Dr. Qiang‐Shuai Gu Xiao‐Yang Dong Xiang Meng Prof. Dr. Xin‐Yuan Liu 《Angewandte Chemie (International ed. in English)》2018,57(26):7668-7672
A copper‐catalyzed asymmetric radical oxytrifluoromethylation of alkenyl oxime and Togni's reagent has been successfully developed, thereby providing straightforward access to CF3‐containing isoxazolines bearing α‐tertiary stereocenters with excellent yield and enantioselectivity. The key to success is the rational design of cinchona‐alkaloid‐based sulfonamides as neutral/anionic hybrid ligands to effectively control the stereochemistry in copper‐catalyzed reactions involving free alkyl radical species. The utility of this method is illustrated by efficient transformation of the products into useful chiral CF3‐containing 1,3‐aminoalcohols. 相似文献
19.
Xin Liu Ze‐Shu Wang Tong‐Yi Zhai Chen Luo Yi‐Ping Zhang Yang‐Bo Chen Chao Deng Rai‐Shung Liu Long‐Wu Ye 《Angewandte Chemie (International ed. in English)》2020,59(41):17984-17990
Here an efficient copper‐catalyzed cascade cyclization of azide‐ynamides via α‐imino copper carbene intermediates is reported, representing the first generation of α‐imino copper carbenes from alkynes. This protocol enables the practical and divergent synthesis of an array of polycyclic N‐heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities. Moreover, an asymmetric azide–ynamide cyclization has been achieved with high enantioselectivities (up to 98:2 e.r.) by employing BOX‐Cu complexes as chiral catalysts. Thus, this protocol constitutes the first example of an asymmetric azide–alkyne cyclization. The proposed mechanistic rationale for this cascade cyclization is further supported by theoretical calculations. 相似文献
20.
Copper‐Catalyzed γ‐Selective and Stereospecific Allylic Cross‐Coupling with Secondary Alkylboranes 下载免费PDF全文
Yuto Yasuda Kazunori Nagao Yoshinori Shido Prof. Dr. Seiji Mori Prof. Dr. Hirohisa Ohmiya Prof. Dr. Masaya Sawamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9666-9670
The scope of the copper‐catalyzed coupling reactions between organoboron compounds and allylic phosphates is expanded significantly by employing triphenylphosphine as a ligand for copper, allowing the use of secondary alkylboron compounds. The reaction proceeds with complete γ‐E‐selectivity and preferential 1,3‐syn stereoselectivity. The reaction of γ‐silicon‐substituted allylic phosphates affords enantioenriched α‐stereogenic allylsilanes. 相似文献