Copper-catalyzed electrophilic amination of diorganozinc reagents

The copper-catalyzed electrophilic amination of diorganozinc reagents employing O-acyl N,N-dialkyl hydroxylamine derivatives as aminating agents is described. This reaction offers a general method for the preparation of tertiary amines in high yields and is noteworthy for its convenience both in terms of reaction conditions employed (room temperature, 相似文献   

Enantioselective Nitrogen Transfer to Sulfides from Nitridomanganese(V) Complexes

We describe the facile preparation of novel, optically active nitridomanganese(V) complexes which serve as reagents for the electrophilic amination of sulfides. This amination method has several appealing features, including: i) the facile preparation of large quantities of the starting nitridomanganese reagent 3 , ii) the preparation of acylsulfilimines 2 in optically active form, and iii) the mild reaction conditions employed.     

Synthesis of 3-Aminopyrocatechol via Lithiated Intermediates

We report the synthesis of 3-aminopyrocatechol (7) through electrophilic amination of lithiated pyrocatechol, protected in the form of a ketal. For this purpose the lithiation reaction of protected pyrocatechol (1) was studied. The synthesis of compounds (3) was achieved by the reaction of organolithium derivative (2) and a series of electrophilic reagents. Lithium-t-butyl-N-tosyloxycarbamate (5) was used as the electrophilic aminating reagent. With the cupro derivative (4) the protecting groups in compound (6) are removed in an acid medium by heating in ethanol-HCl solution (4:1).     

Catalytic enantioselective fluorination and amination of beta-keto phosphonates catalyzed by chiral palladium complexes

[reaction: see text] The catalytic enantioselective fluorination and amination of beta-keto phosphonates catalyzed by chiral palladium complexes is described. Treatment of beta-keto phosphonates with N-fluorobenzenesulfonimide (NFSI) as electrophilic fluorinating reagent and diethyl azodicarboxylate (DEAD) as electrophilic amination reagent under mild reaction conditions afforded the corresponding alpha-substituted beta-keto phosphonates in moderate to excellent yields with excellent enantiomeric excesses.     

Catalytic enantioselective electrophilic α-amination of β-ketoesters catalyzed by chiral palladium complexes

The catalytic enantioselective electrophilic α-amination promoted chiral palladium complexes is described. Treatment of β-ketoesters with azodicarboxylates as electrophilic amination reagents under mild reaction conditions afforded the corresponding α-amino β-ketoesters with excellent enantiomeric excesses (91-99% ee). Palladium complexes were immobilized in [bmim]PF₆, and their applications to catalytic α-amination of β-ketoesters were successfully demonstrated.     

The electrophilic amination of carbanions: an unconventional new entry to C-N bond formation

The electrophilic amination of carbanions allows the preparation of a wide range of amines through an unconventional C-N bond-forming reaction. The concepts behind the varied synthetic approaches, classified by the nature of the aminating agent and of the organometallic species, are discussed. The mild operational conditions, the high selectivity, and the availability of the starting materials are good assets of these processes which nicely complement each other. New appealing and flexible routes can be devised, leading in several cases to the synthesis of otherwise not easily accessible N-containing compounds.     

Copper-catalyzed electrophilic amination of functionalized diarylzinc reagents

The copper-catalyzed electrophilic amination of functionalized diarylzinc reagents with O-acyl hydroxylamines allows for the preparation of functionalized tertiary arylamines in high yields, and is noteworthy for the mild reaction conditions employed. The functionalized diarylzinc reagents were prepared via an iodine/magnesium exchange of the corresponding aryl iodide followed by transmetalation of the resultant Grignard species with ZnCl(2).     

Catalytic enantioselective electrophilic α-hydrazination of β-ketoesters using bifunctional organocatalysts

The catalytic enantioselective electrophilic α-hydrazination promoted by chiral bifunctional organocatalysts is described. Treatment of β-ketoesters with azodicarboxylates as electrophilic amination reagents under mild reaction conditions afforded the corresponding α-amino β-ketoesters with excellent enantiomeric excesses (93-99% ee).     

Electrophilic Amination with Nitroarenes

An exceptionally general electrophilic amination, which directly transforms commercially available nitroarenes into alkylated aromatic aminoboranes with zinc organyl compounds was developed. The reaction starts with a two‐step partial reduction of the nitro group to a nitrenoid, which is used in situ as the electrophilic amination reagent. To facilitate isolation, the resulting air‐ and moisture‐sensitive aminoboranes were reacted with a range of electrophiles. The method not only represents a direct transformation of nitro compounds into electrophilic amination reagents but also provides an elegant alternative to dehydrocoupling methods for the generation of aminoboranes.     

Heterogeneously Porous γ‐MnO2‐Catalyzed Direct Oxidative Amination of Benzoxazole through CH Activation in the Presence of O2

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.     

Enantioselective α-hydrazination of α-fluoro-β-ketoesters catalyzed by chiral nickel complexes

The catalytic enantioselective electrophilic α-hydrazination promoted by chiral nickel complexes is described. Treatment of α-fluoro-β-ketoesters with azodicarboxylates as electrophilic amination reagents under mild reaction conditions afforded the corresponding α-amino α-fluoro-β-ketoesters with high yields (80-96%) and enantioselectivities (up to 78% ee).     

Cosolvent‐promoted electrophilic amination of organozinc reagents

In this study, we aimed to develop a simple and efficient method for the electrophilic amination of organozinc reagents. For this reason, 12 cosolvents were screened in the electrophilic amination of ordinary organozinc reagents. By the use of a cosolvent, an easily applicable and high‐yielding method for the preparation of arylamines by electrophilic amination of arylzinc reagents was developed. Copyright © 2009 John Wiley & Sons, Ltd.     

Electrochemical amination of unsaturated and aromatic compounds

The mechanism and synthetic perspectives of an indirect cathodic amination of unsaturated and aromatic substrates are considered. The influence of experimental conditions on the state and reactivity of the aminating reagent in solution is studied. The key role of the electrolyte acidity and redox properties of the reagents and intermediates in the obtained isomeric composition and the yield of the amination products is demonstrated.     

Photochemical C−H Amination of Ethers and Geminal Difunctionalization Reactions in One Pot

A mild, atom‐economic, and metal‐free α‐C?H amination of ethers using relatively stable nonafluorobutanesulfonyl (nonaflyl, Nf) azide as the aminating reagent to give N‐sulfonyl hemiaminals is reported. This enables unprecedented C(sp³) difunctionalization reactions, leading to diverse functionalized amino group containing compounds starting from simple ethers in one pot.     

Copper‐Catalyzed Electrophilic Amination of Heteroarenes and Arenes by CH Zincation

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.     

Copper‐Catalyzed Electrophilic Amination of Heteroarenes and Arenes by C?H Zincation

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.     

ZrCl4-promoted halogen migration during an electrophilic amination of halogenated phenols

An electrophilic amination of halogenated phenols with diisopropyl diazenedicarboxylate in the presence of ZrCl4 as a Lewis acid, accompanied by a halogen migration, was demonstrated for the first time; the fluorine, chlorine, bromine, or iodine atom migrated during the amination process under mild reaction conditions.     

Eco-Friendly Methodology for the Formation of Aromatic Carbon–Heteroatom Bonds by Using Green Ionic Liquids

A new sustainable method is reported for the formation of aromatic carbon–heteroatom bonds under solvent-free and mild conditions (no co-oxidant, no strong acid and no toxic reagents) by using a new type of green ionic liquid. The bromination of methoxy arenes was chosen as a model reaction. The reaction methodology is based on only using natural sodium bromine, which is transformed into an electrophilic brominating reagent within an ionic liquid, easily prepared from the melted salt FeCl₃ hexahydrate. Bromination reactions with this in-situ-generated reagent gave good yields and excellent regioselectivity under simple and environmentally friendly conditions. To understand the unusual bromine polarity reversal of sodium bromine without any strong oxidant, the molecular structure of the reaction medium was characterised by Raman and direct infusion electrospray ionisation mass spectroscopy (ESI-MS). An extensive computational investigation using density functional theory methods was performed to describe a mechanism that suggests indirect oxidation of Br⁻ through new iron adducts. The versatility of the methodology was successively applied to nitration and thiocyanation of methoxy arenes using KNO₃ and KSCN in melted hexahydrated FeCl₃.     

Anthranil: An Aminating Reagent Leading to Bifunctionality for Both C(sp3)−H and C(sp2)−H under Rhodium(III) Catalysis

Previous direct C?H nitrogenation suffered from simple amidation/amination with limited atom‐economy and is mostly limited to C(sp²)?H substrates. In this work, anthranil was designed as a novel bifunctional aminating reagent for both C(sp²)?H and C(sp³)?H bonds under rhodium(III) catalysis, thus affording a nucleophilic aniline tethered to an electrophilic carbonyl. A tridendate rhodium(III) complex has been isolated as the resting state of the catalyst, and DFT studies established the intermediacy of a nitrene species.     

N‐Trifluoromethylthiosaccharin: An Easily Accessible,Shelf‐Stable,Broadly Applicable Trifluoromethylthiolating Reagent

A new, electrophilic trifluoromethylthiolating reagent, N‐trifluoromethylthiosaccharin, was developed and can be synthesized in two steps from saccharin within 30 minutes. N‐trifluoromethylthiosaccharin is a powerful trifluoromethylthiolating reagent and allows the trifluoromethylthiolation of a variety of nucleophiles such as alcohols, amines, thiols, electron‐rich arenes, aldehydes, ketones, acyclic β‐ketoesters, and alkynes under mild reaction conditions.