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Dr. Jun Wang Marcus Frings Prof. Dr. Carsten Bolm 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):966-969
Kinetic resolution of racemic sulfoxides requires either custom substrates or shows moderate enantioselectivity, leading to achiral coproducts (such as sulfones) as an intrinsic part of the process. A new strategy is demonstrated that allows the resolution of racemic sulfoxides through catalytic asymmetric nitrene‐transfer reactions. This approach gives rise to both optically active sulfoxides and highly enantioenriched sulfoximines. By using a chiral iron catalyst and a readily available iodinane reagent, high selectivity factors have been achieved under very practical reaction conditions. With respect to the substrate scope, it is noteworthy that this unprecedented imidative kinetic resolution of racemic sulfoxides provides access to both aryl–alkyl and dialkyl sulfoximines in highly enantioenriched forms. 相似文献
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Hao Yu Dr. Zhen Li Prof. Dr. Carsten Bolm 《Angewandte Chemie (International ed. in English)》2018,57(1):324-327
Free NH‐sulfoximines were directly prepared from sulfoxides through iron catalysis by applying a readily available, shelf‐stable hydroxylamine triflic acid salt. No additional oxidant is needed, and the substrate scope is broad, including a range of heterocyclic compounds. 相似文献
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Tobias Biberger Szabolcs Makai Dr. Zhong Lian Dr. Bill Morandi 《Angewandte Chemie (International ed. in English)》2018,57(23):6940-6944
Among all metathesis reactions known to date in organic chemistry, the metathesis of multiple bonds such as alkenes and alkynes has evolved into one of the most powerful methods to construct molecular complexity. In contrast, metathesis reactions involving single bonds are scarce and far less developed, particularly in the context of synthetically valuable ring‐closing reactions. Herein, we report an iron‐catalyzed ring‐closing metathesis of aliphatic ethers for the synthesis of substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates. 相似文献
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M. Sc. Isabel T. Alt Prof. Dr. Bernd Plietker 《Angewandte Chemie (International ed. in English)》2016,55(4):1519-1522
The nucleophilic iron complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) catalyzes the direct intramolecular C?H amination of α‐azidobiaryls and (azidoaryl)alkenes into the corresponding carbazoles and indoles, respectively, under mild conditions and with low catalyst loadings. These features and the broad functional‐group tolerance render this method a particularly attractive alternative to established noble‐metal‐based procedures. 相似文献
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Lina Ma Wenjuan Li Hui Xi Xiaohui Bai Enlu Ma Dr. Xiaoyu Yan Prof. Dr. Zhiping Li 《Angewandte Chemie (International ed. in English)》2016,55(35):10410-10413
Exploiting catalytic carbonyl–olefin metathesis is an ongoing challenge in organic synthesis. Reported herein is an FeCl3‐catalyzed ring‐closing carbonyl–olefin metathesis. The protocol allows access to a range of carbo‐/heterocyclic alkenes with good efficiency and excellent trans diastereoselectivity. The methodology presents one of the rare examples of catalytic ring‐closing carbonyl–olefin metathesis. This process is proposed to take place by FeCl3‐catalyzed oxetane formation followed by retro‐ring‐opening to deliver metathesis products. 相似文献
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Dr. Anna Hedström Dr. Zakieh Izakian Irma Vreto Dr. Carl‐Johan Wallentin Prof. Dr. Per‐Ola Norrby 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5946-5953
The radical nature of iron‐catalyzed cross‐coupling between Grignard reagents and alkyl halides has been studied by using a combination of competitive kinetic experiments and DFT calculations. In contrast to the corresponding coupling with aryl halides, which commences through a classical two‐electron oxidative addition/reductive elimination sequence, the presented data suggest that alkyl halides react through an atom‐transfer‐initiated radical pathway. Furthermore, a general iodine‐based quenching methodology was developed to enable the determination of highly accurate concentrations of Grignard reagents, a capability that facilitates and increases the information output of kinetic investigations based on these substrates. 相似文献
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Iron‐Catalyzed Regioselective Transfer Hydrogenative Couplings of Unactivated Aldehydes with Simple Alkenes 下载免费PDF全文
Yan‐Long Zheng Yan‐Yao Liu Yi‐Mei Wu Yin‐Xia Wang Yu‐Tong Lin Prof. Dr. Mengchun Ye 《Angewandte Chemie (International ed. in English)》2016,55(21):6315-6318
An FeBr3‐catalyzed reductive coupling of various aldehydes with alkenes that proceeds through a direct hydride transfer pathway has been developed. With iPrOH as the hydrogen donor under mild conditions, previously challenging coupling reactions of unactivated alkyl and aryl aldehydes with simple alkenes, such as styrene derivatives and α‐olefins, proceeded smoothly to furnish a diverse range of functionalized alcohols with complete linear regioselectivity. 相似文献
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Romain Rey‐Rodriguez Pascal Retailleau Prof. Pascal Bonnet Prof. Isabelle Gillaizeau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3572-3575
Herein the first example of the iron(II)‐catalyzed trifluoromethylation of enamide using mild and simple reaction conditions is reported. The method is cost‐effective and uses the easy‐to‐handle Togni’s reagent as the electrophilic CF3 source. This transformation is totally regioselective at the C3 position of enamides and exhibits broad substrate scope, good functional group tolerance and thus demonstrates its useful application in a late‐stage fluorination strategy. 相似文献
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Jun‐Jie Shen Prof. Shou‐Fei Zhu Dr. Yan Cai Huan Xu Xiu‐Lan Xie Prof. Qi‐Lin Zhou 《Angewandte Chemie (International ed. in English)》2014,53(48):13188-13191
An iron‐catalyzed asymmetric intramolecular cyclopropanation was realized in high yields and excellent enantioselectivity (up to 97 % ee) by using the iron complexes of chiral spiro‐bisoxazoline ligands as catalysts. The superiority of iron catalysts exhibited in this reaction demonstrated the potential abilities of this sustainable metal in asymmetric carbenoid transformation reactions. 相似文献
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Naohisa Nakagawa Prof. Dr. Takuji Hatakeyama Prof. Dr. Masaharu Nakamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(11):4257-4261
An iron‐catalyzed diboration reaction of alkynes with bis(pinacolato)diboron (B2pin2) and external borating agents (MeOB(OR)2) affords diverse symmetrical or unsymmetrical cis‐1,2‐diborylalkenes. The simple protocol for the diboration reaction can be extended to the iron‐catalyzed carboboration of alkynes with primary and, unprecedentedly, secondary alkyl halides, affording various tetrasubstituted monoborylalkenes in a highly stereoselective manner. DFT calculations indicate that a boryliron intermediate adds across the triple bond of an alkyne to afford an alkenyliron intermediate, which can react with the external trapping agents, borates and alkyl halides. In situ trapping experiments support the intermediacy of the alkenyl iron species using radical probe stubstrates. 相似文献
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Dr. Kuntal Pal Oliver B. Hemming Dr. Benjamin M. Day Dr. Thomas Pugh Prof. Dr. David J. Evans Prof. Dr. Richard A. Layfield 《Angewandte Chemie (International ed. in English)》2016,55(5):1690-1693
In the presence of stoichiometric or catalytic amounts of [M{N(SiMe3)2}2] (M=Fe, Co), N‐heterocyclic carbenes (NHCs) react with primary phosphines to give a series of carbene phosphinidenes of the type (NHC)?PAr. The formation of (IMe4)?PMes (Mes=mesityl) is also catalyzed by the phosphinidene‐bridged complex [(IMe4)2Fe(μ‐PMes)]2, which provides evidence for metal‐catalyzed phosphinidene transfer. 相似文献
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Daniele Addis Nadim Shaikh Shaolin Zhou Shoubhik Das Kathrin Junge Dr. Matthius Beller Prof. Dr. 《化学:亚洲杂志》2010,5(7):1687-1691
The reduction of ketones with polymethylhydrosiloxane (PMHS) gives the corresponding alcohols in good to excellent yield applying iron‐based catalyst systems. In the case of prochiral ketones, the use of Fe(OAc)2/(S,S)‐Me‐DuPhos leads to high enantioselectivity up to 99 % ee. The reaction proceeds in the presence of several functional groups such as esters, halides as well as conjugated double bonds, with high chemoselectivity. The advantage of this protocol is that the reaction requires no activating agents or additives. 相似文献
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Tobias Parchomyk Prof. Dr. Konrad Koszinowski 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15609-15613
Iron‐catalyzed cross‐coupling reactions have an outstanding potential for sustainable organic synthesis, but remain poorly understood mechanistically. Here, we use electrospray‐ionization (ESI) mass spectrometry to identify the ionic species formed in these reactions and characterize their reactivity. Transmetalation of Fe(acac)3 (acac=acetylacetonato) with PhMgCl in THF (tetrahydrofuran) produces anionic iron ate complexes, whose nuclearity (1 to 4 Fe centers) and oxidation states (ranging from ?I to +III) crucially depend on the presence of additives or ligands. Upon addition of iPrCl, formation of the heteroleptic FeIII complex [Ph3Fe(iPr)]? is observed. Gas‐phase fragmentation of this complex results in reductive elimination and release of the cross‐coupling product with high selectivity. 相似文献
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Marie Vayer Dr. Sara P. Morcillo Jennifer Dupont Prof. Vincent Gandon Dr. Christophe Bour 《Angewandte Chemie (International ed. in English)》2018,57(12):3228-3232
The borrowing hydrogen strategy has been applied to the ethylation of imines with an air‐stable iron complex as precatalyst. This approach opens new perspectives in this area as it enables the synthesis of unsymmetric tertiary amines from readily available substrates and ethanol as a C2 building block. A variety of imines bearing electron‐rich aryl or alkyl groups at the nitrogen atom could be efficiently reductively alkylated without the need for molecular hydrogen. The mechanism of this reaction, which shows complete selectivity for ethanol over other alcohols, has been studied experimentally and by means of DFT computations. 相似文献