Synthesis of amines by the electrophilic amination of organomagnesium, -zinc, -copper, and -lithium reagents

-lithium


Introduction
][14][15][16] To date various type of aminating reagents have been used in the electrophilic amination of organomagnesium, -zinc, -copper, and -lithium reagents for the introduction of free or protected amino moieties, such as haloamines, substituted hydroxylamines, imines, oxaziridines, oximes, diazonium salts, azodicarboxylates, azides, and metal amides.This review covers the literature published in the last twenty years in detail.In addition, older literature has been mentioned briefly.

Scheme 2
It is observed that the amination reaction was unsuccessful in the absence of TMEDA or in the presence of other additives, such as TMPDA, DABCO, HMTA, PMDTA and DME.The success of the amination reaction in the presence of TMEDA was attributed to the formation of a transition state which can be stabilized by electrostatic interaction between the negatively charged chloride atom of N-chloramine and the magnesium atom (Scheme 3).

Scheme 3
The amination of Grignard reagents with methoxyamine was first shown by Schverdina and Kotscheschkow. 28,29They obtained alkyl and arylamines in good to high yields at -15 ºC.1][32] Reaction of alkylmagnesium reagents with LiNHOCH3 was found to be unsuccessful. 33,34reparation of aniline by the electrophilic amination of phenylmagnesium bromide using Ophenylhydroxylamine as aminating reagent was achieved in high yield. 35ome N,N-dialkyl-O-sulfonylhydroxylamines were reacted with organomagnesium reagents to prepare tertiary amines.But the yields of expected amines were not high. 36Reaction of 1alkynylmagnesium bromides with N,N-dimethyl-O-(methylsulfonyl)hydroxylamine (Me2NOSO2Me) was unsuccessful. 37

Scheme 4
Most O-acylhydroxylamines are not stable at room temperature because of their tendency to isomerize to hydroxamic acids.Therefore, they have not been used so much in the electrophilic amination of carbanions.Copper-II catalyzed reaction of various N,N-dialkyl-Obenzoylhydroxylamines with organomagnesium reagents have been shown by Champbell and Johnson. 39RMgX was added slowly (0.15 mmol/min.)to the mixture of aminating reagent and copper catalyst in THF at room temperature.Tertiary amines were obtained in low to high yields (Scheme 5).But synthesis of secondary amines and N-phenylindole under these reaction conditions failed.It was observed that organomagnesium reagents attacked the C-atom of aminating reagents to form benzophenone, benzhydrol and triphenylmethanol as predominant products in the absence of copper catalysis.But aminating reagents bearing large acyl groups, such as 2,4,6-Me3PhCO2NEt2, gave tertiary amines as the major product (85%).O-(diphenylphosphinyl)hydroxylamine is stable at -20 ºC.It was reacted with various Grignard reagents at low temperature to prepare primary amines. 40,41A higher yield of amine was obtained when RMgCl was used instead of RMgBr.
Organomagnesium reagents are the reagents of choice for N-alkylation reactions of α-imino esters. 42The first studies on this subject were published by Fiaud and Kagan. 43,44They observed that primary Grignard reagents showed the highest regioselection in favor of the N-alkylation.

Scheme 7
The mechanism of this amination reaction was predicted to be as shown in Scheme 8.In the first step, organomagnesium reagent coordinates to the carbonyl group of iminomalonate 4. By this way the electron density of nitrogen atom is decreased.Then the alkyl group attacks the nitrogen atom to form the magnesium enolate.Hydrolysis of this enolate gives the desired amine.

Scheme 8
THF was found to be the most suitable solvent for the N-alkylation reaction.Iodosylbenzene and air oxygen were the most effective oxidants for the oxidation of N-alkylated products.But in the case of oxidation with air, it was necessary to use 10% aqueous Na2SO3 for the work-up procedure otherwise oxygen was not effective.
Oximes are a class of aminating reagents which have been widely used in the electrophilic amination of organomagnesium reagents.There are a limited number of works which employ aldoximes as the aminating reagent in the electrophilic amination of organomagnesium reagents. 51,52][55][56][57] Among a number of O-substituted ketoximes (R2C=NOX, X = H, CH3, (CH3)3Si, Ts, MesSO2) acetone O- (2,4,6-trimethylphenylsulfonyl)oxime 5a was found to be a useful reagent for the amination of arylmagnesium reagents (Scheme 9, Method A). 58,59 Treatment of phenylmagnesium bromide with 5a in diethyl ether-toluene (1:6 by volume) at 75 ºC gave aniline in 58% yield after 40 h.Addition of 10 mol % CuI or 20 mol % MgCl2 as catalyst to the reaction mixture decreased the reaction time to 11 h and 22 h, respectively, without a significant change in the yield.
Reaction of aryl bromides with 5a and magnesium in THF under Barbier conditions allowed preparation of arylamines almost in the same or higher yields as those obtained by the procedure described above after 3 h without the need for any catalyst (Scheme 9, Method B). 60 Arylamines were synthesized by simultaneous addition of THF solutions of the aryl bromide and 5a to magnesium and then heating the mixture under reflux for 3 h.2][63] 4,4'-Bis(trifluoromethyl)benzophenone O-methylsulfonyloxime 6a reacts with primary-, secondary-, tertiary-and cyclo-alkylmagnesium reagents in THF-HMPA, at 0 ºC and in the presence of CuCN.2LiCl as catalyst, to furnish the corresponding amines in high yields.Furthermore, amination of 1-norbornylmagnesium chloride and 1-adamantylmagnesium bromide under these reaction conditions resulted in high yields (82 and 96%, respectively).But in the case of phenylmagnesium bromide the Würtz reaction occurred instead of an amination reaction and aniline formed only in 7% yield but mainly biphenyl in 74% yield.
n-Butylamine and 1-norbornylamine were prepared in 99% and 96% yields, respectively, using 4,4'-bis(trifluoromethyl)benzophenone O-p-tolylsulfonyloxime 6b under reaction conditions of amination with 6a.The success of the reaction of 6b with aryl Grignard reagents in the absence of copper catalyst, depends on the solvent used in the preparation of arylmagnesium reagent.In the case of PhMgBr/THF, amination reaction resulted in 34% yield, but reaction with PhMgBr prepared in diethyl ether afforded the desired product in 62% yield.

Scheme 10
Similar observations were obtained in the reaction of arylmagnesium reagents with 3,3΄,5,5΄tetrakis(trifluoromethylphenyl)benzophenone O-p-tolylsulfonyloxime 7 and functional group containing arylamines were prepared in high yields by the use of corresponding arylmagnesium reagents prepared in diethyl ether (Scheme 10).
O-Sulfonyloximes of ureas and carbonates were screened for the electrophilic amination of organomagnesium reagents. 64It was determined that, in the reaction of diethyl carbonate O-tosyloxime 8 with phenylmagnesium bromide in toluene, the organomagnesium reagent attacked either oxime carbon or the nitrogen atom to afford a mixture of 9a-c and 8 (Eq.1).
Cyclic urea and carbonate O-sulfonyloximes 10-12 (Scheme 11) were reacted with phenylmagnesium bromide and 10 was determined as the most useful aminating reagent for the amination of Grignard reagents prepared in diethyl ether.This oxime is more reactive in toluene as compared to THF.While the Z-isomer of oxime 12 gave only the N-phenylation product, the E-isomer gave C-phenylation reaction.

Scheme 11
Conversion of imine, formed after amination reaction, to aniline under acidic conditions failed.It is found that it can be selectively converted into aniline in high yield by treatment with CsOH.H2O in ethylene glycol at 150 ºC for 1h or to N-methylaniline in high yield by the reduction with LiAlH4 in THF at room temperature for 12 h.
Primary, secondary and tertiary (except t-Bu) alkylmagnesium bromides reacted with compound 10 at -78 ºC, and heteroaryl and functional groups bearing arylmagnesium bromides at 0 ºC to give the corresponding imines, which upon hydrolysis or reduction provide the corresponding amines or N-methylamines, respectively, in good to high yields (Scheme 12).But the hydrolysis and reduction of 2,6-dimethylphenylimine and 4-trifluoromethylphenylimine could not be achieved.In addition, 2-thienylimine could not be converted to the primary amine.

Scheme 13
Compound 13a reacted with aryl and functionalized arylmagnesium reagents prepared in Et2O at room temperature in dichloromethane or at 0 ºC in chlorobenzene to afford the corresponding arylamines in excellent yields after the hydrolysis of the resulting imines with 1 M HCl in Et2O (Scheme 14).Amination of arylmagnesium reagents prepared in THF completed in a longer time while amination in THF was not efficient.Alkyl and cycloalkylmagnesium reagents also reacted with 13a to supply the desired products in high yields after the hydrolysis of the resulting N-alkyl imines under reflux in acidic EtOH.Amination of styryl and isopropenylmagnesium reagents was achieved in excellent yields.
Functionalized aryl Grignard reagents, prepared in THF, give an exothermic reaction with tosyl azide.Treatment of the reaction mixture with Raney nickel and cold aqueous NaOH gives aniline derivatives in yields of up to 82%. 70rylmagnesium reagents, prepared in ether, can be aminated at room temperature using trimethylsilylmethyl azide in good to high yields. 71Phenylmagnesium bromide gives two parallel reactions with triphenylsilyl azide. 72One of these reactions is the substitution of the azide group by the phenyl group of the Grignard reagent to form tetraphenylsilane.The other reaction is the formation of the corresponding triazene salt.Decomposition of this salt at 100-120 ºC, followed by the hydrolysis of the resulting N-(triphenylsily1)amide gives aniline.
Attack of Grignard reagents on azides, bearing electron-withdrawing groups, was assumed to be facilitated by coordination between MgBr2 as shown in Figure 1. 73Trost and Pearson showed that, in the reaction of RYCH2N3 (R: aryl, alkyl, Y: S, O) type heteroatom substituted azides with organomagnesium reagents, the activating influence of sulfur is higher than that of oxygen.In addition they observed that (arylthio)methyl azide was more successful than (alkylthio)methyl azide. 74HS N N N Mg Br Br

Figure 1
Addition of benzyl or butyl azide to the alkylmagnesium reagent in diethyl ether solution provides the corresponding triazene. 69llyl azide 14 can easily be prepared by the reaction of sodium azide with allyl bromide in water in the presence of a catalytic amount of tetrabutylammonium bromide. 75It is used successfully as a synthon for +δ NH2 in the synthesis of arylamines by the electrophilic amination of arylmagnesium reagents (Scheme 15). 76It is reported that azide 14 can be used without purification, but in this case the molar ratio of ArMgX: 14 must be change from 1:1 to 1:1.5.Alkyl Grignard reagents add to aryl azides to form the corresponding mono-N-alkylanilines in high yields (Scheme 16). 77The method works effectively with Grignard reagent bearing both primary and secondary alkyl groups and aliphatic alkyl groups of different chain length.The formation of mono-N-alkylaniline as the only product (no trace of N,N-dialkylaniline) is attributed to the addition of the Grignard reagent to the azide with successive loss of N2, followed by proton capture during aqueous workup to form mono-N-alkylanilines. However, reaction of aryl Grignard reagents with aryl azide afforded the corresponding diazene.This different result was thought to be due to steric factors.

Scheme 16
9][80] However, the yield was higher in THF which has stronger coordination ability. 81rylazo tosylates which can be prepared in a two step-sequence consisting of a diazotation and tosylation of the resulting diazonium tetrafluoroborates, have been used as synthetic equivalents of the electrophilic arylamino synthon in the electrophilic amination of polyfunctional arylmagnesium reagents. 82Polyfunctional diarylamines can be prepared by the addition of functionalized arylmagnesium reagents to functionalized arylazo tosylates, followed by in situ allylation and reductive workup (Scheme 17).
Knochel and co-workers 83 described a procedure for the preparation of polyfunctionalized diarylamines by the reaction of arylmagnesium reagents with nitroarenes (Scheme 18).In this procedure not only organomagnesium reagent but also nitroarene can bear either electronwithdrawing or electron-donating groups.6-Nitrobenzothiazole and 6-nitroquinoline can be arylated using this procedure to obtain the desired arylated amines in good yields.

Scheme 18
In the first step of the mechanism (Scheme 19) addition of the first equivalent of arylmagnesium reagent, followed by the elimination of magnesium phenolate, gives nitrosobenzene.The second equivalent of arylmagnesium reagent attacks the N=O double bond of nitrosobenzene to form diarylhydroxylamine which is reduced to diarylamine (Scheme

Scheme 19
In the case of nitroarenes bearing a bulky substituent next to their nitro group, the second equivalent of arylmagnesium reagent attacks the oxygen atom of the nitroso arene (Scheme 19, path B) to form the corresponding nitrene. 84The amount of arylmagnesium reagent can be decreased from 2.3 equivalents to 1.2 equivalents by the use of nitroso arenes as starting materials (Scheme 20). 85 2

Electrophilic Amination of Organozinc Reagents
7][88] The bond between carbon and zinc has a covalent character and therefore they show modest reactivity towards many electrophilic reagents.This characteristic allows them to tolerate numerous functional groups. 89o date, only a few electrophilic amination procedures have been reported in the literature employing organozinc reagents.Coleman and coworkers reacted dialkylzinc reagents with chloroamines and obtained the desired amine as a mixture with other amines and ammonia 21,90  Recently, a successful study related to the preparation of tertiary amines by the electrophilic amination of diorganozinc reagents with various N,N-dialkyl-N-chloroamines has been published by Barker and Jarvo. 91Diphenylzinc reagent was reacted with chloroamines using bipyridineligated Nickel catalyst.The reaction was carried out in DMA/THF (1:2.4) mixture at 0 ºC and tertiary amines were obtained in moderate to high yields (Scheme 21a).This procedure has a functional group tolerance.For example amination of substrates which have terminal alkene or amide function, using this procedure resulted in good yields of the corresponding tertiary amines.

Issue in
Amination of electron-poor N,N-dialkyl-N-chloroamines such as N-chloroamides and Nchlorosuccinimide under these reaction conditions was found to be unsuccessful.Amination of arylzinc chloride at room temperature gave tertiary amine in moderate yield (55%), but at 0 ºC in high yield (87%).

Scheme 21a
Functional group bearing diorganozinc reagents were also successfully aminated under these reaction conditions (Scheme 21b).

Scheme 21b
Secondary amines can be converted into tertiary amines by a one-pot chlorination and arylation reaction using this procedure (Scheme 22).

Scheme 23
Copper-catalyzed amination of diorganozincs is an exothermic reaction.This warming does not affect the reaction yield in micro-scale.However when the reaction is performed on a largescale it causes a decrease in yield (for example from 91% to 72%) if the reaction temperature is not kept at 5 ºC. 96© ARKAT USA, Inc.

Scheme 24
s-Bu(CH3)2ZnLi, type mixed zincate reacts with lithioalkoxylamides to furnish s-BuNH2 in low yield (18%). 34 CuCN catalyzed amination of diorganozincs and triorganozincates with methoxyamine 15 gives primary arylamines and benzylamine in moderate to high, alkyl and cycloalkyl amines in low to moderate yields. 97,98Addition of a dipolar aprotic solvent as cosolvent leads to an increase in the yields of arylamines and improves the reaction conditions. 99In the case of arylzinc chlorides, amination of functional group bearing arylzinc chloride is more successful than that of phenylzinc chloride (Scheme 25).

Scheme 25
There is a need for a copper catalyst to react organozinc chlorides and diorganozincs with oximes at room temperature.Triorganozincates can react without using any catalyst, but the yield of amine is low. 97,98All three organozinc reagents react with 5a in the presence of CuCN, as catalyst, to give primary amines in low to moderate yields.0][101]  P-, N-, or S-donor ligand causes a significant reduction in the quantity of copper catalysts and a remarkable increase in the yield of amine (Scheme 26). 101here is no need to use a copper catalyst to obtain primary arylamines in good yields, if the amination of arylzinc reagents with acetone oxime O-tosylate 5b, in the presence of a cosolvent, is performed at 40

Scheme 26
Methylarylzinc reagents react with 5a in the presence of CuCN as catalyst to give arylamines in low to moderate yields. 102][105] Diethylzinc reacts with α-ketimino esters 16a-d in toluene at room temperature to produce Nethylation products in high yields (Scheme 27). 105However, the hindered imine ester 16e does not react with diethylzinc.CO  Niwa and coworkers observed that, if the reaction of diethylzinc reagent with 2-[N-(pmethoxyphenyl)imino]malonate 4 at -78 ºC is carried out in toluene in place of THF, the N-ethylation product can be prepared in higher yield (80% instead of 40%).In addition the reaction is completed in a shorter time. 49,50mination of organozinc halides, diorganozincs and lithium triorganozincates with oxaziridines have been studied by Ghoraf and Vidal. 106They found diorganozinc to be the most successful organozinc reagent.Amination reactions of diorganozincs with oxaridine 17 were conducted in Et2O:hexane (1:4) at 0 ºC without using any catalyst.Only n-alkylzincs gave high yields of Boc-protected primary amines.Amination of sec-, tert-, and cycloalkylzinc, and arylzinc reagents resulted in low yields (Scheme 28).

Scheme 28
It is proposed that the oxygen of oxaziridine 17 coordinates to the zinc atom to form the zincate complex 18.This coordination facilitates attack of the organo group on the electrophilic nitrogen to open the oxaziridine ring (Scheme 29).Therefore, ethereal solvents, which can act as competing Lewis bases, must be avoided.Some attempts have been made to use diazonium salts for amination of organozinc reagents.Curtin and Ursprung reacted alkyl, benzyl and arylzinc chlorides with a suspension of aryldiazonium tetrafluoroborates in diethyl ether at 0 ºC to afford the corresponding azo compounds in low yields. 107Attempts to carry out the reaction using a pyridine solution of aryldiazonium tetrafluoroborates resulted in poorer yields.Diorganozinc reagents were found to react with benzenediazonium tetrafluoroborates in xylene-DMF (1:2) or in diethyl ether at 0 ºC very fast and give azo compounds in high yields. 108RKAT USA, Inc.
Erdik and Koçoğlu 109 revisited this amination reaction and showed that triarylzincates prepared by transmetallation of corresponding arylmagnesium reagents with ZnCl2.TMEDA react with benzenediazonium tetrafluoroborate in THF at -15 ºC to give the corresponding arylazo compounds in high yields (Scheme 30).Alkyl, cycloalkyl-, and benzylzincates were found to be unsuccessful.Arylazo compounds were subsequently reduced, using NaBH4/NiCl2.6H2O, and arylamines were obtained as a mixture with aniline in low to moderate yields.

Scheme 30
It is observed that triarylzincate, prepared separately, gave higher yields compared with in situ prepared triarylzincate, whereas in situ prepared arylzinc chloride was more successful than arylzinc chloride prepared separately.Rieke and coworkers reported a procedure for the preparation of primary amines using organozinc halides and di-tert-butyl azodicarboxylate (DBAD) 19 in three steps. 110They performed the first step in high yields (Scheme 31).In this step, organozinc halide reacts with DBAD at 0 ºC to afford di-tert-butylhydrazinodicarboxylates in moderate to high yields after hydrolysis with NaHCO3.In the second step, the tert-butoxycarbonyl groups can be removed with CF3COOH.And finally, the primary amines can be obtained after reductive cleavage of the N-N bond using H2/Raney Ni.

Scheme 31
Recently, functionalized arylazotosylates have been used as aminating reagents in the preparation of secondary aryl-alkylamines by the electrophilic amination of alkylzinc halides and dialkylzinc reagents (Scheme 32). 111The cleavage of the N-N bond was performed using Raney nickel in refluxing ethanol.

Electrophilic Amination of Organocopper Reagents
Organocopper reagents are indispensible in the field of synthetic organic chemistry.They have been used not only for the synthesis of simple organic molecules, but also for the synthesis of various types of natural products with high chemo-, regio-and stereoselectivity. 112o date, most aminating reagents, for the electrophilic amination of mono-organocopper and cuprates were based on sp 3 -hybridized nitrogen species.For example, N,N-dimethyl-O-(methylsulfonyl)hydroxylamine (Me2NOSO2Me) 113 and N,N-dimethyl-O-(diphenylphosphinyl)hydroxylamine (Me2NOPOPh2) 37 were used for electrophilic amination of higher order 1alkynylcuprates, to obtain the corresponding amines in poor to high yields.
4-(Benzoyloxy)piperidine reacts with phenylcopper and diphenylcuprate to furnish aniline in good to high yields (Scheme 33). 39Diphenylcuprate gives a higher yield than phenylcopper.The organometallic precursor (PhLi, PhMgBr or PhZnCl) used in the preparation of organocopper reagents does not affect the yield, but using a Li2CuCl3 complex instead of a CuBr.SMe2 complex as copper source leads to an increase in the yield of aniline.34). 114According to the proposed mechanism of Ricci et.al., in the first step of the amination reaction, one of the R groups in R2CuCNLi2 abstracts one proton from the aminating reagent to give a lower-order cyanocuprate and lithium N-silyl-N-siloxamide (nitrenoid), 21a.After the formation of 21a, depending on the type of R group in the lithium organylcyanocuprate, nitrenoid-oxenoid (21a-21b) equilibrium may occur.If R is an aryl group, lithium arylcyanocuprate reacts with 21a without allowing formation of 21b, and gives the corresponding silylated amine (Scheme 34 path A).However, if R is an alkyl group, the 21a-21b equilibrium may occur, and the cyanocuprate reacts with both the nitrenoid and the oxenoid to give amine and alcohol (Scheme 34 Path B).
N-Alkylarylamines and N-alkylheteroarylamines were prepared in moderate to high yields by the electrophilic amination of higher-order cyanocuprates with N-alkylhydroxylamines (Scheme 35). 115N-alkyl-O-trimethylsilylhydroxylamines react with higher-order cyanocuprates at room temperature, whereas 20 reacts at low temperatures.
Genêt and co-workers [116][117][118][119] have developed new electrophilic amination reagents (Scheme 36) for the direct transfer of the N-protected moiety to a nucleophilic site.These types of reagents are useful, especially when the synthesis of sensitive primary amines, which are otherwise not stable as free bases, is needed.Scheme 36 These reagents were found to be suitable for the electrophilic amination of arylcopper and dialkylcuprates but not for diarylcuprates and diarylcyanocuprates (Scheme 37a).The use of (MgCl)BTOC, 22a ' , supplied alkylamines in higher yields than that of LiBTOC 22a, in the amination of dialkylcuprates.In the case of amination of PhCu, LiBTOC was more successful.

Scheme 37b
Electrophilic amination of dialkylcuprates with 22a-c was presumed to be an SN2 process in which the aminating reagent interacted with the dimeric cuprate to form an intermediate and a mechanism very similar to that proposed for the electrophilic amination of 20 with diarylcyanocuprates 114 was suggested.
Yamamoto and Maruoka, 120 described the preparation of secondary and tertiary amines based on the oxidative coupling of lithium diorganylcopper amides, which were generated from lithium dialkyl(or diaryl)cuprates and alkyl-, cycloalkyl-, benzyl-, or aryl-primary or secondary amines.Iwao and co-workers 121 reported a procedure for the oxidative coupling reaction of ortholithiated benzamides with anilido-chloro or -cyano cuprates to yield substituted N-aryl anthranyl amides.In both studies, five equivalents of cuprate were utilized with respect to the amine and molecular oxygen as an oxidant at -78-25 ºC.
Dembech, Ricci and co-workers described the synthesis of aliphatic, aromatic, and heteroaromatic amines by oxidative coupling of lithium-and zinc-amidocyanocuprates in which one equivalent of cuprate with respect to the amine was used. 122,123A number of secondary and tertiary amines were synthesized by N-alkylation, -vinylation, -arylation, and -heteroarylation of simple primary and secondary amines using this procedure (Scheme 38).It was observed that the preparative method of the amidocuprate did not cause any major change in the yield of products.

Scheme 39
Chloranil was proposed to coordinate to the copper center of the amidocuprate as shown in Scheme 40 during oxidation of the lithium amidocuprate.

Scheme 40
Iodophenyldiacetate (PhI(OAc)2) was used as the oxidizing reagent for amidocuprates obtained from heteroaromatic zinc reagents and the corresponding primary, secondary and tertiary amines were formed in good to high yields (Scheme 41). 126
Organolithium reagents react with azides in the same way as organomagnesium reagents to give 1,3-disubstituted triazenes.6][147] Aryl-and heteroaryllithiums reacted with vinyl azides to give the corresponding aromatic amines in moderate to good yields after an acidic hydrolysis. 148Allyl azide was found to be a useful reagent for the conversion of phenyllithium to aniline (61%) using hexane as the solvent. 76rganolithiums cannot be aminated with (pheny1thio)methyl azide without using MgBr2 because of the lower Lewis acidity of lithium salts. 73It was reported that the reaction of (trimethylsilyl)methyl azide with aryllithiums in diethyl ether, followed by hydrolysis, generated the corresponding aromatic amines in poor yields (35-41%). 149Diphenyl phosphorazidate reacts easily with aryl-and heteroaryllithiums to give the corresponding amino compounds after reduction of triazene formed with sodium bis(2-methoxyethoxy)aluminum hydride. 150

Conclusions
Electrophilic amination of organometallic reagents is an important and useful synthetic method for the preparation of aliphatic, aromatic and heteroaromatic amines and is continuing to gain the