Amines telomerization

This section deals with catalyzed aminations in aqueous phases, so the developments discussed here must have some water in the reaction mixture. AH reactions known to synthesize amines via catalysts in the presence of water can be divided into four categories and are discussed in the following order Hartwig—Buchwald aminations, telomerization to yield amines, reductive aminations/hydroamino-methylations, and aUyhc aminations. 

Although acetonitrile is one of the more stable nitriles, it undergoes typical nitrile reactions and is used to produce many types of nitrogen-containing compounds, eg, amides (15), amines (16,17) higher molecular weight mono- and dinitriles (18,19) halogenated nitriles (20) ketones (21) isocyanates (22) heterocycles, eg, pyridines (23), and imidazolines (24). It can be trimerized to. f-trimethyltriazine (25) and has been telomerized with ethylene (26) and copolymerized with a-epoxides (27). 

Isoprene (2-methyl-1,3-butadiene) can be telomerized in diethylamine with / -butyUithium as the catalyst to a mixture of A/,N-diethylneryl- and geranylamines. Oxidation of the amines with hydrogen peroxide gives the amine oxides, which, by the Meisenheimer rearrangement and subsequent pyrolysis, produce linalool in an overall yield of about 70% (127—129). 

Telomerization Reactions. Butadiene can react readily with a number of chain-transfer agents to undergo telomerization reactions. The more often studied reagents are carbon dioxide (167—178), water (179—181), ammonia (182), alcohols (183—185), amines (186), acetic acid (187), water and CO2 (188), ammonia and CO2 (189), epoxide and CO2 (190), mercaptans (191), and other systems (171). These reactions have been widely studied and used in making unsaturated lactones, alcohols, amines, ethers, esters, and many other compounds. 

Similarly, Itexafluoroprapylene undergoes fluoride ion induced homotelo-merization to give a series of dimers and trimers These telomerizations can be induced by other nucleophiles, such as amines Indeed, the selectivity of the pi oce-,s can be changed significantly by varying reagents and reaction conditions [25, 26] (equations 19 and 20)... 

Nielsen DJ, Cavell KJ (2006) Pd-NHC complexes as catalysts in telomerization and aryl amination reactions. In Nolan SP (ed) N-Heterocyclic carbenes in synthesis. WUey-VCH, Weinheim, pp 73-102... 

In an analoguous case, two-phase telomerization of butadiene with ammonia to give octadienylamine has been reported where higher selectivity is realized in a two-phase system of water-toluene. Here, octadienylamine is more reactive than ammonia and consecutive reaction leads to sec and ten amines. By adopting a two-phase strategy, a primary amine selectivity as high as 91 % has been realized (Drieben-Hoscher and Keim, 1998). 

Bayer (1997) has claimed that in a water-CH2Cl2 system, using water soluble Pd(OAc)2 -triphenylphosphine trisulphonic acid catalyst, octa-2,7-dienyl-l-amine and octa 1,7-dienyl -3-amine can be obtained by telomerization of butadiene with ammonia. 

Scheme4-5 Intermediates in the hydroamination vs. telomerization ofl,3-dienes 4.4.2.2 Activation ofthe Amine 4.4.2.2.1 Activation by Bases...

These telomerization reactions of butadiene with nucleophiles are also catalyzed by nickel complexes. For example, amines (18-23), active methylene compounds (23, 24), alcohols (25, 26), and phenol (27) react with butadiene. However, the selectivity and catalytic activity of nickel catalysts are lower than those of palladium catalysts. In addition, a mixture of monomeric and dimeric telomers is usually formed with nickel catalysts ... 

The most characteristic reaction of butadiene catalyzed by palladium catalysts is the dimerization with incorporation of various nucleophiles [Eq. (11)]. The main product of this telomerization reaction is the 8-substituted 1,6-octadiene, 17. Also, 3-substituted 1,7-octadiene, 18, is formed as a minor product. So far, the following nucleophiles are known to react with butadiene to form corresponding telomers water, carboxylic acids, primary and secondary alcohols, phenols, ammonia, primary and secondary amines, enamines, active methylene compounds activated by two electron-attracting groups, and nitroalkanes. Some of these nucleophiles are known to react oxidatively with simple olefins in the presence of Pd2+ salts. Carbon monoxide and hydrosilanes also take part in the telomerization. The telomerization reactions are surveyed based on the classification by the nucleophiles. 

Amines with higher basicity showed higher reactivity. For example, the yields of the 1 1 adducts of morpholine (pK = 9.61), aniline (9.42), n-butylamine (3.39), and piperidine (2.80) were 79, 67, 19, and 29%, respectively. Telomerization of butadiene with diethylamine catalyzed by... 

The linear telomerization reaction of dienes was one of the very first processes catalyzed by water soluble phosphine complexes in aqueous media [7,8]. The reaction itself is the dimerization of a diene coupled with a simultaneous nucleophilic addition of HX (water, alcohols, amines, carboxylic acids, active methylene compounds, etc.) (Scheme 7.3). It is catalyzed by nickel- and palladium complexes of which palladium catalysts are substantially more active. In organic solutions [Pd(OAc)2] + PPhs gives the simplest catalyst combination and Ni/IPPTS and Pd/TPPTS were suggested for mnning the telomerizations in aqueous/organic biphasic systems [7]. An aqueous solvent would seem a straightforward choice for telomerization of dienes with water (the so-called hydrodimerization). In fact, the possibility of separation of the products and the catalyst without a need for distillation is a more important reason in this case, too. 

Many new sugar based products present the advantage of being non-toxic and biodegradable. The products resulting from the telomerization of 1 with appropriate nucleophiles such as alcohols, amines, water, or carbon dioxide serve generally as useful intermediates in the synthesis of various natural products and fine chemicals [60-63], as precursors for plasticizer alcohols [56, 64], components of diesel fuels [65], surfactants [11, 66], corrosions inhibitors, and non-volatile herbicides [67]. 

The telomerization of butadiene by means of water in ILs was described by Dullius et Rottger et al. report a process for the telomerization of acyclic olefins having at least two conjugated double bonds, or their mixtures, using a palladium-carbene complex as catalyst in an IL solvent. The nucleophiles included water, alcohols, phenols, polyols, carboxylic acids, ammonia and primary and secondary amines. The acycylic olefins could be either 1,3-butadiene or isoprene. 

The telomerization of dienes in a two-phase system was first described in a patent (100). Water was used as the solvent for the catalyst, with sulfonated phosphane ligands providing the water solubility. Water, alcohols, phenols, acids, amines, and acetylacetic add were used as nucleophiles. 

Trialkylamines are used as additives in the telomerization of butadiene and water in a two-phase system (103). The catalyst comprises a palladium salt and tppms or tppts. The amines may build cationic surfactants under catalytic conditions and be capable of micelle formation. The products include up to five telomerization products (alcohols, alkenes, and ethers), and thus the reaction is nonselective. 

Primary amines can be synthesized selectively by the catalytic two-phase telomerization of butadiene and ammonia [Eq. (12)], provided that the two amines are extracted from the aqueous catalyst phase with a polar solvent immediately after their synthesis (104). 

Eberhardt et al. 169 170) found that TMEDA, sparteine or other ditertiary amines enable the telomerization of ethylene with benzene by lithium alkyls to yield molecules of the general formula C6H5(CH2CH2)nH. A valuable compilation has been made of related studies employing polyamine chelated alkali metal compounds87). 

Eberhardt and co-workers (12, 13) found that lithium alkyls are active toward the telomerization of ethylene and benzene when a tert-amine or chelating diamine, such as sparteine or N.N.JV. Af -tetramethylenethy-lenediamine (TMEDA), is used [Eqs. (1)—(3)]. 

Maddock SM, Finn MG (2000) Palladium-catalyzed head-to-head telomerization of isoprene with amines. Organometallics 19 2684—2689... 

Several catalytic systems have been investigated for hydroamination of unsaturated bonds [16]. Takahashi et al. reported the telomerization of 1,3-dienes in the presence of an amine leading to octadienylamine or allylic amines when palladium catalysts are used in association with monodentate or bidentate phosphine ligands, respectively [17]. Dieck et al. demonstrated the beneficial effect of addition of an amine hydroiodic salt in the hydroamination reaction of 1,3-dienes in which the allylic amines are produced via an intermediate Jt-allyl palladium complex [18]. Coulson reported the Pd-catalyzed addition of amines to allenes where dimerization is incorporated [4]. This reaction presumably proceeds via a cyclic palladium intermediate in which the Pd activates the olefinic bond for nucleophilic attack the reactions are therefore different from pronucleophilic additions. 

Less attention has been paid to the use of amines as nucleophiles in the telomerization reaction. A single report from Nolan and co-workers [233] has shown that well-defined cationic palladium complexes are efficient catalysts in the telomerization of butadiene with amines under mild conditions (Table 10). In the case of primary amines, the concentration of the reactants and their steric hinderance dictates the formation of a mono- or double-alkylated product. 

Table 10 Telomerization of butadiene with various amines a...

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