Alcoholic Palladium Chloride Reactions

In alcoholic solution, the conjugated diene-palladium chloride reaction yields 7r-(l-alkoxyethyl)allyl derivatives, indicating that the chloro group may easily be replaced by... 

Example 86 A 0.10 mole amount of the starting 3-(4-hydroxyphenyl) propylene, 0.25 mole of methyl nitrite, 0.5 liter of methyl alcohol, and 0.006 mole of a palladium chloride catalyst were charged into a reaction vessel. Then, the reaction was carried out at a temperature of 20.degree. C. for 1.5hours."... 

According to Skita, the reaction proceeds in a different manner if the reduction be effected with palladium chloride and hydrogen. In this case the citral in alcoholic solution is mixed with an aqueous solution of palladium chloride and the whole thickened with gum-arabic. Hydrogen gas is then forced into this solution under pressure. The products of the reduction include citronellal and citronellol and a di-molecular aldehyde, C Hj O, which probably has the following constitution —... 

The palladium-catalyzed cross-coupling reaction featured in this procedure occurs under neutral conditions in the presence of many synthetically useful functional groups (e.g. alcohol, ester, nitro, acetal, ketone, and aldehyde). The reaction works best in N,N-dimethylformamide with bis(triphenylphosphine)palladium(ll) chloride, PdCI2(PPh3)2, as the catalyst. Lithium chloride is added to prevent decomposition of the catalyst.143 13 It is presumed that conversion of the intermediate aryl palladium triflate to an aryl palladium chloride is required for the transmetallation step to proceed.9... 

The mechanism of the Zn chloride-assisted, palladium-catalyzed reaction of allyl acetate (456) with carbonyl compounds (457) has been proposed [434]. The reaction involves electroreduction of a Pd(II) complex to a Pd(0) complex, oxidative addition of the allyl acetate to the Pd(0) complex, and Zn(II)/Pd(II) transmetallation leading to an allylzinc reagent, which would react with (457) to give homoallyl alcohols (458) and (459) (Scheme 157). Substituted -lactones are electrosynthesized by the Reformatsky reaction of ketones and ethyl a-bromobutyrate, using a sacrificial Zn anode in 35 92% yield [542]. The effect of cathode materials involving Zn, C, Pt, Ni, and so on, has been investigated for the electrochemical allylation of acetone [543]. 

Alkenes can be converted to succinic esters by reaction with carbon monoxide, an alcohol, and palladium chloride in the presence of mercuric chloride.1,12 The addition is mostly syn. In similar reaction, both terminal and internal alkynes can be converted to esters of maleic acid. 

Tetrakis(triphenylphosphine)-palladium(O), 289 Tin(IV) chloride, 300 Trimethylamine N-oxide, 325 Zinc amalgam, 347 Homoallylic alcohols By addition reactions of allyl to carbonyl groups... 

Diphenyl selenide is a colourless, strongly refractive oil, B.pt. 167° C. at 16-5 mm. insoluble in water but miscible with alcohol or ether in all proportions. It has a faint odour, and a density of 1 3712 at 0° C., 1 3561 at 15 2° C., and 1 350 at 20° C. With cold bromine in ether solution it yields the dibromide. Diphenyl selenide, unlike dimethyl selenide, does not combine with alkyl iodides, and in this respect it resembles diphenyl sulphide.2 When heated nearly to its boiling-point with sulphur it gives diphenyl sulphide, the reaction being practically quantitative at 300° C.3 With palladium chloride it forms the complex PdCl2.2(C6H5)2Se, orange-red needles, M.pt. 181° to 182° C.4... 

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... 

Abnormal olefin arylation reactions which are of interest mechanistically and preparatively occur with some allylically substituted compounds. The ailylic esters and ethers appear normal and produce cinnamyl derivatives exclusively while ailylic alcohols and chlorides are abnormal. Ailylic alcohols and "arylpalladium acetates form 3-arylaldehydes from primary ailylic alcohols and 3-arylketones from secondary alcohols 3°). The mechanism of reaction apparently involves anti-Markovnikov addition of the palladium compound to the double bond followed by elimination of the hydrogen atom on the hydroxyl-bearing carbon rather than the benzylic hydrogen. This again would be elimination of the more electronegative hydrogen atom. 

This reaction, as written, would be catalytic in palladium chloride but in practice it is only partially catalytic because some of the palladium salt is reduced in a side reaction. The side reaction is the arylation of the product allylaromatic compound and this occurs because the product is more reactive towards the "arylpalladium chloride than allyl chloride is. This side reaction, producing 1,3-diaryipropenes, can be minimized by using an excess of the allylic chloride. The allylation and allylic alcohol arylation are both tolerant of the same variations in structure and substituents as is the arylation reaction and therefore are of considerable synthetic utility. 

Telomerization of Isoprene.—Reviews have appeared on isoprene and chloro-prene, and on the complex reactions of isoprene to form terpenoids (in Japanese). Isoprene reacts with magnesium, especially in the presence of Lewis acids, and the resulting complex gives adducts with aldehydes. As usual in this type of reaction, a very complex mixture is obtained. The palladium-chloride-catalysed reaction of isoprene with acetic acid gives different products in different solvents. Monomers predominate in benzene [2-methylbut-2-enyl acetate (5) and 3-methylbut-2-enyl acetate (6)] while dimers [(7), (8), neryl (9), and geranyl (10) acetates] tend to be formed in tetrahydrofuran. Further details of the synthesis of Cio alcohols from isoprene and naphthyl-lithium are available, as well as of the in situ oxidation,but there is little of novelty (see Vol. 1, p. 17). 

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]. 

Into the glass reaction vessel is placed three liters of either methyl or ethyl alcohol. To this is added 236 grams (262 ml) of allylbenzene. If methyl alcohol is used, 750 ml of water is then added. If 190 proof spirit is used, then only 630 ml of water is added because it already contains 5% water. Then 28 grams of palladium chloride is added. The adventuresome experimenter may dissolve the palladium chloride into the water added to the reaction instead of putting them in separately. This converts the PdC12 into the hydrate, which is much more soluble in the water portion of the solution. 

There is a way around the hasslesome purification procedure that will allow the underground chemist to use the ethyl nitrite he has made quickly and easily. The way to do this is to bubble the vapors of the ethyl nitrite into the reaction mixture. This method avoids the unpleasant and possibly dangerous procedure with the sep funnel and subsequent distillation. See Figure 8 back in Chapter 4 on N-methyl formamide. If in that figure, the methylamine containing flask instead contained the ethyl nitrite reaction mixture, and the formic acid containing flask instead had the allylbenzene and palladium chloride in alcohol needed for phenylacetone production, then one could easily picture how to get the ethyl nitrite vapors to directly bubble into the phenylacetone production mix without any need to manipulate the nitrite directly. 

G-Allylic urethanes and carbonates are afforded from amines/alcohols, carbon dioxide and allylic chlorides by palladium catalysed reaction in the presence of an organobase. The choice of added base in the generation of carbamates/carbonates was critical for high yields... 

As early as 1963, Tsuji and colleagues described the reaction of olefin-palladium chloride complexes with CO to produce jS-chloroacyl chlorides [1,2]. Both internal and terminal aliphatic olefins were transformed into the corresponding chloroesters when the reaction was conducted in alcohols. Later on, in 1969, Yukawa and Tsutsumi reported on the reaction of a styrene-palladium complex with CO in alcohols [3]. Here, various cinnamates and phenylsuccinates were synthesized. Compared with Tsuji s work, they proposed a different reaction mechanism. They assumed that the oxidative addition of the alkyloxycarbonyl groups into styrenes is the key step, but a stoichiometric amount of palladium was stiU necessary to perform the reaction. Another version of a dialkoxycarbonylation of olefins was reported by Heck [4], using mercuric chloride as additive. 

The acylation of arenes with alcohols has been shown to be possible using a palladium chloride catalyst in the presence of f-butylhydroperoxide. In 2-arylpyridines, substitution is directed to the ortho-position and, after initial paUadation, the formation of intermediate (59) is likely before reductive elimination yields the acylated product. The regioselective acetoxylation of indoles, at the 3-position, has been achieved using the palladium-catalysed reaction with phenyliodonium acetate. 3-Acyl indoles may also be prepared using acetyl chlorides with zirconium tetrachloride as a Lewis acid catalyst. 

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