Direct alkenylation of arylamines at the ortho-position

Treatment of magnesium alkylidene carbenoids, which were generated from 1-chlorovinyl p-tolyl sulfoxides with isopropylmagnesium chloride at −78 °C in toluene, with N-lithio arylamines gave ortho-alkenylated arylamines in moderate to good yields. The reaction was found to proceed in a highly stereospecific manner at the carbenoid carbon. This reaction offers a quite novel and direct alkenylation of arylamines at the ortho-position of the aromatic ring.     

Cyclopropylation of arylamines at the 2-position with cyclopropylmagnesium carbenoids

Direct cyclopropylation of arylamines at the 2-position with 1-chlorocyclopropyl phenyl sulfoxides was achieved. The reaction of N-lithio arylamines with cyclopropylmagnesium carbenoids, which are generated from 1-chlorocyclopropyl phenyl sulfoxides with i-PrMgCl via the sulfoxide-magnesium exchange reaction, is the key of this procedure. This method offers an unprecedented way for the synthesis of arylamines having a cyclopropane ring at the 2-position directly from arylamines.     

Direct alkenylation of arylamines at the ortho-position with magnesium alkylidene carbenoids and some theoretical studies of the reactions

1-Chlorovinyl p-tolyl sulfoxides were synthesized from ketones and chloromethyl p-tolyl sulfoxide in high yields. Treatment of the sulfoxides with isopropylmagnesium chloride at −78 °C in toluene gave magnesium alkylidene carbenoids (α-chloro alkenylmagnesium chlorides), which were treated with N-lithio arylamines to afford ortho-alkenylated arylamines in moderate yields. The reaction, in some cases, proceeded in a highly stereospecific manner at the carbon bearing the chlorine and the sulfinyl group. The structures of the α-chloro alkenylmagnesium chlorides and the reactivity of the N-lithio meta-substituted anilines were studied at the B3LYP and MP2 levels of theory with the 6-31(+)G* basis set. This reaction offers a quite novel and direct alkenylation of arylamines at the ortho-position of the aromatic ring.     

Unusual Skeletal Reorganization of Oxetanes for the Synthesis of 1,2‐Dihydroquinolines

Skeletal reorganization is a type of fascinating transformations owing to their intriguing mechanisms and utility in complex molecule synthesis. However, only a limited amount of examples are known for most functional groups. Herein, we describe such an unusual process of oxetanes. In the presence of In(OTf)₃ as catalyst, oxetane‐tethered anilines reacted unexpectedly to form 1,2‐dihydroquinolines. This process not only provides expedient access to dihydroquinolines, but also represents a new reaction of oxetane. Mechanistically, it is believed that the reaction proceeds through initial nitrogen attack rather than arene attack followed by a series of bond cleavage and formation events. Control experiments provided important insights into the mechanism.     

Alkaloid synthesis using 2nd generation palladium-catalyzed cycloalkenylation. Diastereoselective total synthesis of α-skytanthine

An efficient approach to the synthesis of 3-azabicyclo[3.3.0]octanes and 3-azabicyclo[4.3.0]nonanes by 2nd generation palladium-catalyzed cycloalkenylation is described. Additionally, this reaction is used for the diastereoselective total synthesis of (±)-α-skytanthine.     

Gold(III)-mediated aldol condensations provide efficient access to nitrogen heterocycles

Quinolines, dihydroquinolines, and aza-xanthones can be synthesized efficiently and under mild reaction conditions by means of a reaction sequence employing Au(III)-catalyzed aldol reactions as the key step.     

Reactions of highly electrophilic polyfluorocarbonyl compounds with primary arylamines

C-Hydroxyalkylation of primary arylamines by highly electrophilic polyfluorocarbonyl compounds results from the direct reaction of the initial reagents and is competitively inhibited by equilibrium N-hydroxyalkylation. The presence of steric hindrances to the formation of N-hydroxyalkylation products and an increase in the ring C-nucleophilicity facilitate the C-hydroxyalkylation reaction.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 383–389, February, 1990.     

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.     

[(S)-BINAP]PdBr2-catalyzed direct synthesis of 2,3-disubstituted indoles via a tandem reaction between arylamines and α-diketones

A direct PdBr₂(BINAP)-complex catalyzed method has been developed to produce 2,3-disubstituted indoles by the reaction of arylamines with α-diketones under reductive (H₂) conditions. The synthetic methodology involves a tandem reaction of three steps and all the organic intermediates were isolated and characterized, the reduction products in this sequence are chiral and present interesting enantiomeric excess. This report constitutes a new and different route to synthesize indoles and a plausible mechanism is also suggested.     

芳酰基硒脲合成及其对O~2清除作用的EPR研究

芳酰基硒脲的合成试剂芳酰基异硒氰酸脂是极不稳定的化合物。通过硒氰化铅在非极性溶剂苯中同芳酰氯反应能简便、稳定和可靠地合成芳酰基异硒氰酸脂、从而与芳胺反应能合成一系列芳酰基硒脲。经EFR 研究其对超氧阴离子自由基O~2具有明显的清除作用。     

Nickel‐Catalyzed N‐Alkylation of Acylhydrazines and Arylamines Using Alcohols and Enantioselective Examples

A borrowing‐hydrogen reaction between amines and alcohols is an atom‐economic way to prepare alkylamines, ideally with water as the sole byproduct. Herein, nickel catalysts are used for direct N‐alkylation of hydrazides and arylamines using racemic alcohols. Moreover, a nickel catalyst of (S )‐binapine was used for an asymmetric N‐alkylation of benzohydrazide with racemic benzylic alcohols.     

Reaction of magnesium carbenoids with N-lithio arylamines: a novel method for generation of non-stabilized α-amino-substituted carbanions and a new synthesis of α-amino acid derivatives

Treatment of 1-chloroalkyl phenyl sulfoxides with a Grignard reagent at low temperature afforded magnesium carbenoids in quantitative yields. The magnesium carbenoids were found to be reactive with N-lithio alkylamines and N-lithio arylamines. The reaction with N-lithio alkylamines afforded an olefin, which was derived from dimerization of the magnesium carbenoid, in moderate yield. The reaction with N-lithio arylamines gave the adducts, α-amino-substituted carbanions, in good yields. From these intermediates, a novel synthesis of α-amino acid derivatives and N,N-dialkyl arylamines having a deuterium at the α-position was realized.     

Cycloaddition dipolaire-1,3 des arylnitriloxydes sur les dihydro-1,2 quinoleines n-substituees

The 1,3-dipolar cycloaddition reaction of arylnitrile oxideson 1,2- dihydroquinolines gives two adducts if the nitrogen atom of the dipolarphile carries benzoyl group. On the other hand the reaction provides only one adduct in the N-substituentis benzyl group. The structure of the cycloadducts has been established by spectroscopic and chemical method.     

Reaction of acridine proton salts with arylamines in the presence of sulfur

The reaction of acridine proton salts with arylamines in the presence of sulfur was studied. It is shown that various arylamines of the benzene and naphthalene series, both free and substituted, form the corresponding aminoarylacridines in high yields in this reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 112–114, January, 1971.     

Synthesis and structure of aroylamidines and <Emphasis Type="Italic">N</Emphasis>-arylbenzamidines hydrochlorides

Aroylamidines can be obtained as salts in a reaction of the corresponding arylcarbonitriles with anhydrous ethanol in the presence of dry HCl followed by treating intermediate imidoesters with alcoholic solution of ammonia. N-Arylbenzamidines are obtained by reacting benzonitrile with arylamines in the presence of AlCl₃. The structure of arylamines and the reaction conditions significantly affect the yield of the target product, and sometimes the very possibility of its preparation.     

Alkylation of quinoline and isoquinoline in the presence of LiCl

EEDQ and EEDI generated in situ by the reaction of quinoline and isoquinoline with diethyl pyrocarbonate was treated with alkylating reagents having an activated carbon such as diethyl malonate, ethyl acetoacetate etc. in the presence of 0.5 equiv of LiCl in acetonitrile to provide the corresponding alkyl dihydroquinolines and alkyl dihydroisoquinolines in high yields.     

Regioselective Synthesis of Functionalized Dihydroquinolines via Organocatalytic Allylic Alkylation

The regioselective allylic alkylation of 1,2-dihydroquinolines and Morita-Baylis-Hillman(MBH) adducts has been developed. By surveying various reaction parameters, we summarized the effects of temperatures, relative reactant doses, catalysts, solvents and N-protected groups on the regioselectivity of this transformation. This method provides a facile protocol for the preparation of allylic α-substituted dihydroquinolines.     

Some aspects of palladium-catalyzed cycloalkenylation: developments of environmentally benign catalytic conditions and demonstration of tandem cycloalkenylation

The influences of catalysts, substituent groups, and solvents on the palladium-catalyzed cycloalkenylation of cross-conjugated silyl enol ethers of 2-tert-butyldimethylsiloxy-5-(2-propenyl)-1,3-cyclohexadiene derivatives have been investigated. The catalytic reaction proceeded smoothly, even in aqueous media. The product ratios were influenced by the structure of substrates as well as solvents. In addition, it was found that the reaction is applicable to a tandem cyclization for the construction of cedrane skeleton.     

Enantioselective boronate additions to N-acyl quinoliniums catalyzed by tartaric acid

Tartaric acid catalyzes the asymmetric addition of vinylboronates to N-acyl quinoliniums, affording highly enantioenriched dihydroquinolines. The catalyst serves to activate the boronate through a ligand-exchange reaction and generates the N-acyl quinolinium in situ from the stable quinoline-derived N,O-acetal.     

Solvent-free and direct C(sp)–H amination of adamantanes by grinding

A facile, direct and environmentally benign conversion of C(sp³)–H bonds to C(sp³)–N bonds using substoichiometric amount of aprotic superelectrophiles polyhalomethane–AlX₃ has been achieved by grinding under solvent-free conditions at room temperature in air. It is a general and simple method for the direct amination of adamantanes, and a series of aminoadamantanes of azoles, arylamines or heteroarylamines were obtained in good to excellent yields. The advantages of this amination are atom economy, solvent-free, chemoselectivity, short reaction time and high yields.