Lithium compounds amination

The silylated tin compound 199, obtained from tributyltin hydride and N-bis(trimethylsilyl)propargylamine (198) in the presence of a trace of AIBN (2,2/-azobisisobutyronitrile), is a versatile reagent for the preparation of allylic amines. Treatment with aryl bromides ArBr (Ar = Ph, 4-MeOCgH4, 4-O2NC6H4 etc.) under Pd(PPh3)4 catalysis yields the silylated amines 200, which are hydrolysed by acids to the free amines 201. 199 is converted into the lithium compound 202, which is transformed into 203 by aqueous ammonium chloride and into 204 by the action of alkyl halides RX (R = Me, Et or allyl) (equation 76)204. 

Another potentially useful amination procedure utilizes the reaction of organo-lithium compounds with mixtures of methoxyamine and methyllithium (Eqn. (85)) 343> for example ... 

The methodology to synthesize polymer hybrids by living anionic polymerization is shown in Fig. 3 [30]. Polyolefins containing p-tolyl groups have been used to initiate anionic polymerization by the lithiation of the methyl moiety using alkyl lithium and amine compounds system. 

Aminomethylotion. The reagent reacts with Grignard reagents to form N,N-bis(trimethylsilyl)amines in 60-90% yield (equation I). A similar reaction with organo-lithium compounds requires added magnesium biomide for satisfactory yields. ... 

The Birch and Benkeser reactions of some unsaturated organic compounds [318 and references therein], which consist of a reduction by sodium or lithium in amines, can be mimicked electrochemically in the presence of an alkali salt electrolyte. The cathodic reaction is not the deposition of alkali metal on the solid electrode but the formation of solvated electrons. Most of the reactions described were performed in ethylenediamine [319] or methylamine [308,320]. A feature of these studies is variety introduced by the use of a divided or undivided cell. In a divided cell, the product distribution appears to be the same as that in the classic reduction by metal under similar conditions. In contrast, in an undivided cell the corresponding ammonium salt is formed at the anode it plays the role of an in situ generated proton donor. Under such conditions, the proton concentration... 

The crucial reagents for the synthesis of the enantioemiched lithium compound (iS)-2 are (-)-sparteine complexes of simple alkyllithium bases. P. Beak and cowokers showed that f-BuLi and i-PrLi complexed by (-)-sparteine could be efficiently used for an asymmetric deprotonation reaction, whereas complexes of the chiral amine and t-BuLi or n-BuLi showed hardly any stereoselectivity or reactivity (Scheme 3) [2]. 

Azodicarboxylate esters are the reagents of choice for electrophilic N-amino amination leading to hydrazine derivatives. Besides Grignard reagents and alkyl or aryl lithium compounds,enolates and silyl enol ethersderived from ketones have been aminated by this method. In particular, di-r-butyl azodicarboxylate has been reacted with a variety of chiral enolates (Scheme I9)i03->o and chiral silyl ketene acetds (Schemes 20 and to afford a-hydrazino acid derivatives with high dia-... 

Solution-polymerized SBR is made by termination-free, anionic/live polymerization initiated by alkyl lithium compounds. Other lithium compounds are suitable (such as aryl, alkaryl, aralkyl, tolyl, xylyl lithium, and ot/p-naphtyl lithium as well as their blends), but alkyl lithium compounds are the most commonly used in industry. The absence of a spontaneous termination step enables the synthesis of polymers possessing a very narrow molecular weight distribution and less branching. Carbon dioxide, water, oxygen, ethanol, mercaptans, and primary/secondary amines interfere with the activity of alkyl lithium catalysts, so the polymerization must be carried out in clean, near-anhydrous conditions. Stirred bed or agitated stainless steel reactors are widely used commercially. 

Very often lithium enolates, e.g., those produced with lithium diisopropylamide, yield only low levels of deuterated carbonyl compounds when treated with deuterium oxide or deuterated alcohols (see table below). This is due to the fact that the secondary amine formed becomes involved in the protonation162. Deuterated acids, e.g., diisopropyl (2/ ,3/ )-2,3-dihydroxy-<72-butanedioate behave in a similar way, however, the observed enantioselectivities are somewhat higher. The complex from which a deuteron (or proton) is transferred probably contains lithium enolate, amine and the proton source (see also Section 2.1.6.1.2.). 

Our background with chelate complexes suggested the use of Group IA and IIA metal salts for selective polyamine complexation. The specificity of the interaction between alkali-metal and alkaline-earth salts and certain polyamines provides a sensitive technique for separating single polyamines from multicomponent samples. These separations, the factors that affect complex formation, and the unique properties of the poly-tertiary amine chelates of inorganic lithium compounds are discussed in this paper. 

Ethylenation of n-butyllithium, phenyllithium, and benzylic lithium compounds does not occur at low temperature and ordinary pressure (9). Under more rigorous conditions, telomerization of ethylene in aromatic hydrocarbons proceeds vigorously in the presence of an organolithium compound and an amine. Although n-butyllithium is introduced initially, rapid transmetalation occurs to the more acidic aromatic hydrocarbon (telogen) which subsequently adds to ethylene (taxogen) and initiates the carbanionic polymerization of ethylene. This polymerization proceeds to modest molecular weight, but it is terminated by transmetalation back to the aromatic hydrocarbon which initiates another chain to complete the catalytic cycle. 

Up to now only the reaction of lithiated diethylaminoallene with trimethylchloro-silane, resulting in (exclusively) Me3SiCH2C=C—NEt2, has been reported [104]. The metallation of the easily accessible 2-alkynylamines [6] can be brought about with BuLi /-BuOK in THF. Under suitable conditions free allenic amines can be obtained in a reasonable state of purity if the protonation is carried out with the lithium compounds (obtained from 2-alkynylamines and BuLi in THF, see Ref. [219]), the ratio of allenic and acetylenic amine is less favourable [9]. 

Arylimines can be obtained by the addition of N-silylated amides to aryl-lithium compounds (Scheme 200) 44 the imines may be isolated or reduced in situ to amines, or hydrolysed to carbonyl compounds. a-Ketodicarboxylic acid chloride imine chlorides, which readily undergo cyclization to N-heterocycles, have been prepared by -addition of dicarboxylic acid chlorides to isocyanides (Scheme 201).444 Two new formimidoylamino-substituted carbapenems (4) have been prepared by a route involving a hetero Diels-Alder reaction (Scheme 4).14... 

The synthetic procedure is very critical. In our case, we believe that the imido-lithium compound (Li2NR) is present in the solution of butyl lithium and para-toluidine, in diethyl ether, as reported for the dilithiated a-naphtylamine. This is a noticeable difference in comparison to typical preparations of ruthenium, osmium, and iridium imido complexes, " in which a dichlorometal complex and the monolithium salt (LiNHR) in a molar ratio 1 2, appropriate for a ftA-amido precursor, are used. In these cases a subsequent removal of amine, or a dehydro-halogenation step with LiNHR, is required to afford the products and free amine. Equation (1) summarizes our synthetic procedure ... 

Georges and co-workers used the Dimroth rearrangement in their synthesis of substituted verdazyl compounds as templates for the diversity-oriented synthesis of heterocyclic compounds. Verdazyl derivative 71 did not undergo rearrangement to form 72 when refluxed in ethyl acetate (not shown). However, treatment of 71 with either two equivalents of sodium hydride at room temperature or lithium diisopropyl amine in THF at 0 °C gave the corresponding Dimroth product 72 in 82% yield. 

Lithium tetrahydridoaluminate Amines from nitro compounds... 

A notable exception to the emphasis on free-radical polymerization studies was provided by Karl Ziegler and his co-workers who extended the study of the alkali metal polymerization of dienes to include metals other than sodium and various metal alkyls. Of particular interest were the results obtained with the simplest Group I alkali metal, lithium. It was found that when lithium metal was used as a polymerization initiator 1,4- structures predominated over 1,2-polymers. It was also found that polymerization in hydrocarbon solvents further favoured production 1,4- structures whilst polymerization in polar liquids such as ethers and amines often favoured the formation of 1,2- units. It was also found that reaction of lithium with monomer led to the production of an organo-lithium compound which made feasible homogeneous polymerization—a discovery which eventually led to commercial exploitation. 

Whereas nucleophilic addition of alkyl-lithium compounds to the optically pure arene(tricarbonyl)chromium complex (8) proceeds without asymmetric induction, the chelates (9) react to give amines (10), after hydrolysis, with optical purity of up to 94%." Replacement of the phenyl groups on the azomethine function by alkyl groups should provide an efficient route to a large number of chiral amines. 

It was anticipated that the copolymerization of substituted 1,1-dipheny-lethylenes with dienes such as butadiene and isoprene would be complicated by the very unfavorable monomer reactivity ratio for the addition of poly(-dienyl)lithium compounds to 1,1-diphenylethylene [133, 134]. Yuki and Oka-moto [133, 134] calculated values of ri=54 and ri=29 in hydrocarbon solutions for the copolymerization of 1,1-diphenylethylene (M2) with butadiene (Mi) and isoprene (Mi), respectively. Although the corresponding values in THE are ri(butadiene)=0.13 and ri(isoprene)=0.12, this would not be an acceptable solution since THE is known to form polymers with high 1,2-microstructures [3]. Anionic copolymerizations of butadiene (Mi) with excess l-(4-dimethyla-mino-phenyl)-l-phenylethylene (M2) were conducted in benzene at room temperature for 24-48 h using scc-butyllithium as initiator [189]. Anisole, triethy-lamine and ferf-butyl methyl ether were added in ratios of [B]/[RLi]=60, 20, 30, respectively, to promote copolymerization and minimize 1,2-enchainment in the polybutadiene units. Narrow molecular weight distribution copolymers with Mn=14xl0 to 32x10 (Mw/Mn=1.02-1.03) and 8, 12, and 30 amine... 

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