Highly efficient catalytic system for electrophilic amination of arylzinc reagents

The effect of catalyst on the yield of amine in the amination of three classes of arylzinc reagents with acetone oxime O‐tosylate was investigated. Since they allowed the preparation of arylamines in excellent yields in the presence of a minimum amount of copper (I) or copper (II) compounds, the catalytic systems using copper (I) or copper (II) combined with a P‐, N‐ or S‐donor ligand were revealed to be the best catalysts for the electrophilic amination of arylzinc reagents with acetone oxime O‐tosylate in the presence of DMPU. Copyright © 2009 John Wiley & Sons, Ltd.     

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.     

Palladium‐Catalyzed Amination of Aryl Sulfides with Anilines

A combination of a palladium–NHC catalyst and potassium hexamethyldisilazide enables the amination of aryl sulfides with anilines to afford a wide variety of diarylamines. The reaction conditions are versatile enough for the reaction of even bulky ortho‐substituted aryl sulfides. This amination can be applied to the modular synthesis of N‐aryl carbazoles from the corresponding ortho‐bromothioanisoles. As aryl sulfoxides undergo extended Pummerer reactions to afford ortho‐substituted aryl sulfides, the Pummerer products are thus useful substrates for the amination to culminate in efficient syntheses of a 2‐anilinobenzothiophene and an indole as proof‐of‐principle of the utility of the extended Pummerer reaction/amination cascade.     

High yielding electrophilic amination method for arylcopper reagents

The facilitative effect of some P-, N-, S-, and O-donor ligands in the reaction of arylcoppers with acetone O-(mesitylenesulfonyl)oxime was examined to develop a synthesis method for functionalized primary aryl amines under mild reaction conditions. Our research showed that electrophilic amination of monoaryl coppers with ketoximes can be facilitated using appropriate ligand to supply significant increase in the yield. Also, we have seen that this ligand-facilitated method is applicable in terms of arylcopper and ketoxime type and allows synthesis of primary aryl amines in good to high yields easily at room temperature in very short reaction time.     

Highly functionalized organomagnesium reagents prepared through halogen-metal exchange

Organomagnesium reagents occupy a central position in synthetic organic and organometallic chemistry. Recently, the halogen-magnesium exchange has considerably extended the range of functionalized Grignard reagents available for synthetic purposes. Functional groups such as esters, nitriles, iodides, imines, or even nitro groups can be present in a wide range of aromatic and heterocyclic organomagnesium reagents. Also various highly functionalized alkenyl magnesium species can be prepared. These recent developments as well as new applications of organomagnesium reagents in cross-coupling reactions and amination reactions will be covered in this Review.     

Aryl C-N bond formation by electrophilic amination of diarylcadmium reagents with O-substituted ketoximes

Diorganocadmium reagents cannot react with ketoxime at room temperature. CuCN catalysis allows diarylcadmium reagents to react with ketoxime and to give corresponding arylamines in good to high yields at room temperature. According to the electronic effects of the substituent attached to the aromatic ring, functionalized diarylcadmium reagents show meta-para selectivity in their amination reactions. Also compared to diarylzinc reagents, diarylcadmium reagents react with O-substituted ketoxime under milder reaction conditions and they form corresponding arylamines in higher yields. CuCN cannot help dialkyl-, dicycloalky-, and dibenzylcadmium reagents to react with ketoxime. Our Aryl C-N bond formation method does not include cadmium excretion into the environment.     

Competitive kinetic study of the amination of organomagnesium and ‐zinc reagents with acetone O‐sulfonyloxime

Kinetic studies are reported for the electrophilic amination of substituted phenylmagnesium bromides and CuCN‐catalyzed phenylzinc chlorides with acetone O‐(2,4,6‐trimethylphenylsulfonyl)oxime in tetrahydrofuran at reflux temperature and at room temperature respectively. Substituent effects were determined by competition experiments. Rate data are analyzed via Hammett relationships to support the proposed mechanisms for the substitution of these organometallics with an electrophilic amino transfer reagent. Copyright © 2005 John Wiley & Sons, Ltd.     

Studies on the Amination of Aryl Chlorides with a Monoligated Palladium Catalyst: Kinetic Evidence for a Cooperative Mechanism

Combined spectroscopic, crystallographic, and kinetic studies of the mechanism of aromatic amination with the efficient dinuclear Pd precatalyst [Pd₂Cl(μ‐Cl)PtBu₂(Bph‐Me)] (Bph‐Me=2′‐methyl‐[1,1′‐biphenyl]‐2‐yl) have revealed overlapping, yet cooperative, mechanistic scenarios, the relative weights of which are strongly influenced by the products formed as the reaction proceeds. The stability and evolution of the precatalyst in solution has been studied and several metalation pathways that point to a single monoligated intermediate have been identified. Our work sheds light on the nature of the catalytic species involved in the process and on the structure of the corresponding catalytic network.     

[FeIII(F20‐tpp)Cl] Is an Effective Catalyst for Nitrene Transfer Reactions and Amination of Saturated Hydrocarbons with Sulfonyl and Aryl Azides as Nitrogen Source under Thermal and Microwave‐Assisted Conditions

[Fe^III(F₂₀‐tpp)Cl] (F₂₀‐tpp=meso‐tetrakis(pentafluorophenyl)porphyrinato dianion) is an effective catalyst for imido/nitrene insertion reactions using sulfonyl and aryl azides as nitrogen source. Under thermal conditions, aziridination of aryl and alkyl alkenes (16 examples, 60–95 % yields), sulfimidation of sulfides (11 examples, 76–96 % yields), allylic amidation/amination of α‐methylstyrenes (15 examples, 68–83 % yields), and amination of saturated C? H bonds including that of cycloalkanes and adamantane (eight examples, 64–80 % yields) can be accomplished by using 2 mol % [Fe^III(F₂₀‐tpp)Cl] as catalyst. Under microwave irradiation conditions, the reaction time of aziridination (four examples), allylic amination (five examples), sulfimidation (two examples), and amination of saturated C? H bonds (three examples) can be reduced by up to 16‐fold (24–48 versus 1.5–6 h) without significantly affecting the product yield and substrate conversion.     

Synthesis of Benzimidazoles and Benzoxazoles Using Palladium Bis(2,2,6,6-tetramethyl-3,5-heptanedionate) as a Novel Catalyst

Structurally well-defined palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate) complex is reported to be an efficient catalyst for the synthesis of benzimidazole and benzoxazole derivatives in good yields. A novel approach for one-pot synthesis of benzimidazoles via direct reductive amination and N-arylation followed by hydrogenation–cyclization methodology is also described.     

Reductive Amination of Aldehydes and Ketones in a Heterogeneous System in THF and under Solvent-Free Conditions Using Sodium Borohydride-Silica Phosphoric Acid

Summary. A chemoselective, fast, efficient, and high yielding method for the preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica phosphoric acid in THF and under solvent-free conditions at room temperature is described.     

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   

Selective Monoarylation of Primary Amines Using the Pd‐PEPPSI‐IPentCl Precatalyst

A single set of reaction conditions for the palladium‐catalyzed amination of a wide variety of (hetero)aryl halides using primary alkyl amines has been developed. By combining the exceptionally high reactivity of the Pd‐PEPPSI‐IPent^Cl catalyst (PEPPSI=pyridine enhanced precatalyst preparation, stabilization, and initiation) with the soluble and nonaggressive sodium salt of BHT (BHT=2,6‐di‐tert‐butyl‐hydroxytoluene), both six‐ and five‐membered (hetero)aryl halides undergo efficient and selective amination.     

A Facile Synthesis of N-Aryl Substituted Piperidones

A general and efficient procedure for the synthesis of N‐aryl‐substituted 4‐piperidones was developed. The two step syntheses proceeded with an overall yield of 60%‐83% using L‐proline as the ligand for the Cu(I)‐catalyzed Ullmann amination followed by subsequent hydrolysis of resulting ketals.     

Direct Asymmetric Reductive Amination for the Synthesis of Chiral β‐Arylamines

The highly efficient and direct asymmetric reductive amination of arylacetones catalyzed by an iridium complex for the preparation of enantiomerically pure β‐arylamines is described. The monodentate phosphoramidite ligand exhibits superb reactivity (TONs of up to 20 000) and enantioselectivity (up to 99 % ee). Additives played important roles in this reductive coupling reaction.     

Catalytic Enantioselective Desymmetrisation as a Tool for the Synthesis of Hodgkinsine and Hodgkinsine B

Two palladium‐catalysed amination protocols are deployed in the desymmetrisation of the complex dimeric alkaloid meso‐chimonanthine. The power of these transformations is showcased in an efficient formal and total synthesis of the natural products hodgkinsine and hodgkinsine B, respectively.     

Metal-free sequential dual oxidative amination of C(sp3)–H bonds: A direct approach to benzothiadiazine 1,1-dioxide derivatives

An efficient and metal-free Di-tert-butyl peroxide (DTBP)-promoted dual oxidative amination annulation of 2-amino arylsulfonamide with methylarene has been developed. This protocol provides straightforward access to benzothiadiazine 1,1-dioxide derivatives without using prefunctionalized substrates in good to excellent yields with good functional group tolerance.     

Regioselective Intermolecular Allylic C−H Amination of Disubstituted Olefins via Rhodium/π‐Allyl Intermediates

A method for catalytic intermolecular allylic C−H amination of trans ‐disubstituted olefins is reported. The reaction is efficient for a range of common nitrogen nucleophiles bearing one electron‐withdrawing group, and proceeds under mild reaction conditions. Good levels of regioselectivity are observed for a wide range of electronically diverse trans ‐β‐alkyl styrene substrates.     

Concatenating Suzuki Arylation and Buchwald–Hartwig Amination by A Sequentially Pd-Catalyzed One-Pot Process—Consecutive Three-Component Synthesis of C,N-Diarylated Heterocycles

The concatenation of Suzuki coupling and Buchwald-Hartwig amination in a consecutive multicomponent reaction opens a concise, modular and efficient one-pot approach to diversely functionalized heterocycles, as exemplified for 3,10-diaryl 10H-phenothiazines, 3,9-diaryl 9H-carbazoles, and 1,5-diaryl 1H-indoles, in high yields starting from simple staring materials. Moreover, this one-pot reaction is a sequentially palladium-catalyzed process that does not require additional catalyst loading after the first coupling step.     

Asymmetric Dearomatization of β‐Naphthols through an Amination Reaction Catalyzed by a Chiral Phosphoric Acid

A highly efficient catalytic asymmetric dearomatization of naphthols by means of an electrophilic amination reaction catalyzed by chiral phosphoric acid is presented. This protocol provides a facile access to functionalized β‐naphthalenone compounds with a chiral quaternary carbon center in excellent yields and enantioselectivity (up to 99 % yield, up to 96 % ee).