Aminations palladium chloride

Lithium acetylide-Ethylenediamine. Sodium acetylide. Sodium bistrimethylsilylaraide. Carbonylation of primary amines Palladium chloride. 

Terminal monoalkenes were alkylated by stabilized carbanions (p a 10-18) in the presence of 1 equiv. of palladium chloride and 2 equiv. of triethylamine, at low temperatures (Scheme l).1 The resulting unstable hydride eliminate to give the alkene (path b), or treated with carbon monoxide and methanol to produce the ester (path c).2 As was the case with heteroatom nucleophiles, attack at the more substituted alkene position predominated, and internal alkenes underwent alkylation in much lower (=30%) yield. In the absence of triethylamine, the yields were very low (1-2%) and reduction of the metal by the carbanion became the major process. Presumably, the tertiary amine ligand prevented attack of the carbanion at the metal, directing it instead to the coordinated alkene. The regiochemistry (predominant attack at the more sub-... 

When either an alcohol or an amine function is present in the alkene, the possibility for lactone or lactam formation exists. Cobalt or rhodium catalysts convert 2,2-dimethyl-3-buten-l-ol to 2,3,3-trimethyl- y-butyrolactone, with minor amounts of the 8-lactone being formed (equation 51).2 In this case, isomerization of the double bond is not possible. The reaction of allyl alcohols catalyzed by cobalt or rhodium is carried out under reaction conditions that are severe, so isomerization to propanal occurs rapidly. Running the reaction in acetonitrile provides a 60% yield of lactone, while a rhodium carbonyl catalyst in the presence of an amine gives butane-1,4-diol in 60-70% (equation 52).8 A mild method of converting allyl and homoallyl alcohols to lactones utilizes the palladium chloride/copper chloride catalyst system (Table 6).79,82 83... 

Palladium catalysts that are free of halide ions effect the dimerization and carboxylation of butadiene to yield 3,8-nonadienoate esters. Palladium acetate, solubilized by a tertiary amine or an aromatic amine, gives the best yields and selectivities (equation 57).87 Palladium chloride catalyzes the hydrocarboxylation to yield primarily 3-pentenoates.88 The hydrocarboxylation of isoprene and chloroprene is regio-selective, placing the carboxy function at the least-hindered carbon (82% and 71% selectively) minor amounts of other products are obtained (equation 58). Cyclic dienes such as 1,3-cyclohexadiene and 1,3-cyclooctadiene are similarly hydrocarboxylated. 

Over 35 years ago, Richard F. Heck found that olefins can insert into the metal-carbon bond of arylpalladium species generated from organomercury compounds [1], The carbopalladation of olefins, stoichiometric at first, was made catalytic by Tsutomu Mizoroki, who coupled aryl iodides with ethylene under high pressure, in the presence of palladium chloride and sodium carbonate to neutralize the hydroiodic acid formed (Scheme 1) [2], Shortly thereafter, Heck disclosed a more general and practical procedure for this transformation, using palladium acetate as the catalyst and tri-w-butyl amine as the base [3], After investigations on stoichiometric reactions by Fitton et al. [4], it was also Heck who introduced palladium phosphine complexes as catalysts, enabling the decisive extension of the ole-fination reaction to inexpensive aryl bromides [5],... 

Simple terminal alkenes or tranx-disubstituted alkenes gave good yields of the formal addition product when three equivalents of a secondary amine (dimethyl- or diethyl-, but not diisopropylamine) and bis(benzonitrilc)palladium chloride were used at low temperature, after reduction of the C-Pd bond. The yields were modest to very low with (Z)- or cyclic alkenes and using primary amines9, l0. 

In combination with the incremental advances concerning reaction conditions in recent years, especially for low-pressure carbonylations, there is a trend toward increasing use of this chemistry to synthesize advanced building blocks. In this respect carboxylation of alkenes with an appropriate alcohol or amine function leads to the formation of lactones or lactams. Thus, cobalt, rhodium, or palladium chloride/copper chloride catalysts convert allyl and homoallyl alcohols or amines to the corresponding butyrolactones or butyrolactams, respectively [15]. 

A new route to an isocyanate is by combination of an amine with carbon monoxide in the presence of palladium chloride ... 

Compound la is prepared by reacting bis(benzonitrile)palladium chloride with butadiene in benzeneTHF or acetone - at RT. In methanol, the methoxy complex Ib is formed instead ", and in acetic acid the acetate Ic is produced . Additional examples of nucleophiles are sulfinates and amines. The E groups are readily displaced e.g., CH3O, acetate and (CH3)2N can be rapidly displaced in the presence of catalytic amounts of acid. 

The first paper that demonstrated the feasibility of a palladium-catalyzed amination was a report by T. Migita and co-workers.6 They demonstrated that a tri-ortho-tolyl phosphine palladium chloride catalyst will catalyze the cross-coupling of N,N-diethylamino-tributyltin with bromobenzene. The process can be thought of as an amino-Stille cross-coupling. 

Bulky phosphines, such as (/-Bu)3P, were shown to provide a palladium catalyst which is able to aminate and chlorides at room temperature with secondary amines of all type along with anilines.35,53,54,55 Primary amines give very low yields, except if coupling an o-tolyl aryl chloride. In addition, Hartwig has shown that NaOH may be used as a base under biphasic conditions (toluene/aq. NaOH) with a phase transfer catalyst (Ci6H33NMe3Br). 

Borohydride-reduced palladium. Reduction of palladium chloride in methanol with sodium borohydride until evolution of a gas ceases leads to a black material, which is not particularly sensitive to air and is not pyrophoric. The material is useful for selective hydrogenations. It catalyzes rapid hydrogenation of bonds of the type C=C, N=N, and N=0, but not the type C=N and C=0. Nohydrogenolysisof nitrogen or oxygen functions is observed in alcohols, amines, amides, esters, ethers, or lactones. Epoxides are opened to alcohols very slowly. 

A different type of overcrowding is found in chloro methyIdi-[(6-methyl-2-pyridyl)methyl]amine palladium(n) chloride (51), where the chloro-iigand is displaced by 0.93 A from the plane of the three Pd-N bonds, so that the intramolecular Cl C(methyl) contact is 3.29 A. The Pd-Ci distance is 2.331(3) A the mean Pd-N(pyridyl) distance of 2.068(8) A is significantly longer than the Pd-N(amine) distance of 2.018(8) A. ... 

Cl5H19Cl2N3Pd, Chloro(methyldi-((6-methyl-2-pyridyl)methyl)amine)-palladium(Il) chloride, 38B, 921... 

Allylamines can be synthesized in good yield by treatment of n-allyl palladium chloride complexes with amines (Akermark and Zetterberg, 1975). Highest yields and fastest reactions occurred when a coordinating ligand such as tri-n-butylphosphine was present. In the example given, the reaction is stereospecific ( -olefin), but in some instances small quantities of the Z-isomer were isolated, as well as an isomeric allylamine. 

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