Palladium chloride, compound with

Arylpalladium salts ArPdX prepared from arylmercury compounds and lithium palladium chloride couple with allylic chlorides in moderate yields,... 

The palladium chloride reacts with olefins in a different course if water is present. Carbonyl compounds rather than chlorides are formed. The reaction with ethylene produces acetaldehyde and it can be done catalyticaUy in the presence of oxygen and cupric chloride, which is known as the Wacker process. The process is one of the most important commercially useful reactions employing transition metal catalysts. ... 

The synthesis of thiepins 14 was unsuccessful in the case of R1 = i-Pr,79 but if the substituents in the ortho positions to sulfur arc /erf-butyl, then thiepin 14 (R1 = t-Bu R2 = Me) can be isolated in 99% yield.80 Rearrangement of diazo compound 13 (R1 = t-Bu R2 = H), which does not contain the methyl group in position 4, catalyzed by dimeric ( y3-allyl)chloropalladium gives, however, the corresponding e.w-methylene compound. The thiepin 14 (R1 = t-Bu, R2 = H) can be obtained in low yield (13 %) by treatment of the diazo compound with anhydrous hydrogen chloride in diethyl ether at — 20 C.13 In contrast, the ethyl thiepin-3,5-or -4,5-dicarboxylates can be prepared by the palladium catalysis method in satisfying yields.81... 

The allylation of aldehydes can be carried out using stannous chloride and catalytic cupric chloride or copper in aqueous media." In-situ probing provides indirect (NMR, CV) and direct (MS) evidence for the copper(I)-catalyzed formation of an allyltrihalostannane intermediate in very high concentration in water (Scheme 8.6). Hydrophilic palladium complex also efficiently catalyzes the allylation of carbonyl compounds with allyl chlorides or allyl alcohols with SnCl2 under aqueous-organic... 

Arylmercury compounds are also often used as starting materials for the synthesis of palladium(ll) complexes. These reactions, whose reagents and products are compiled in Table 3, typically involve the use of chloromercurio derivatives with palladium chloride complexes (entries a-d). 93>95>179-i8i Similar procedures have been applied to the synthesis of ruthenium(ll) and gold(m) complexes (entries e and f).181,182... 

Treatment of aromatic nitro compounds with allylmagnesium chloride, followed by 1.4 equiv. of LiAlH LAH) and a trace of palladium on charcoal affords hydroxylamines 387 (Ar = Ph, 4-CIC6H4, 2-FC6H4 or 3-MeOC6H4). If the amount of LAH is increased to 2.5 equiv. iV-allylarylamines 388 result. 1-Nitrohexane and nitrocyclohexane react analogously426. 

Palladium catalysts are more often modified for special selectivities than platinum catalysts. Palladium prepared by reduction of palladium chloride with sodium borohydride Procedure 4, p. 205) is suitable for the reduction of unsaturated aldehydes to saturated aldehydes [i7]. Palladimn on barium sulfate deactivated with sulfur compounds, most frequently the so-called quinoline-5 obtained by boiling quinoline with sulfur [34], is suitable for the Rosenmund reduction [i5] (p. 144). Palladium on calcium carbonate deactivated by lead acetate Lindlar s catalyst) is used for partial hydrogenation of acetylenes to cw-alkenes [36] (p. 44). 

Metal-Halogen Compounds. An unusual example of the addition of a metal halide to a conjugated diene has been reported. The complex formed from palladium chloride and butadiene has been shown to be a dimer of 1-chloromethyl-7r-allylpalladium chloride, (85). Whether this is a true insertion reaction or some type of ionic reaction has not been determined, but its close analogy with the olefin-palladium chloride insertion reaction mentioned above would suggest an insertion mechanism for the diene reaction also. 

One of the first compounds to be introduced to the clinic, aztreonam (40-9), has been produced by total synthesis. Constmction of the chiral azetidone starts with amide formation of L-threonine (40-1) via its acid chloride treatment with ammonia leads to the corresponding amide (40-2). The primary amino group in that product is then protected as its carbobenzyloxy derivative (40-3). Reaction of that product with methanesulfonyl chloride affords the mesylate (40-4). Treatment of that intermediate with the pyridine sulfur trioxide complex leads to the formation of the A -sulfonated amide (40-5). Potassium bicarbonate is sufficiently basic to ionize the very acidic proton on the amide the resulting anion then displaces the adjacent mesylate to form the desired azetidone the product is isolated as its tetrabutyl ammonium salt (40-6). Catalytic hydrogenation over palladium removes the carbobenzyloxy protecting group to afford the free primary amine (40-7). The... 

These are prepared by the cyclization of either an arsenous chloride (29) (23JCS2489) or an arsenic acid (30) (58JCS1719). These routes have been used to prepare both the 1-methyl-and the 1-phenyl-arsindolines. The arsindolines show the normal properties of tertiary arsines and form addition compounds with alkyl halides or palladium dibromide. Attempts to dehydrogenate arsindolines to the parent arsindoles (31) have not been successful (Scheme 7). 

This compound is stable to air and humidity but decomposes on heating to give Cs Pdl,], which in turn reduces further to the metal. The chloride salts M2[PdCl6] (M = NH4, alkali metal) may also be reduced readily to the corresponding palladium(II) species with halogen loss at 200 °C.326,329 Both Cs2[PdI6] and (NH4)2[PdCU] have K PtCU type structures328,330 (Pd—Cl in the latter complex is 2.3 A). Vibrational spectra of [Pd ]2- have been reported and these are summarized in Table 6. 

In the case of experiments performed under the conditions of run 6, but in the presence of 1 ml of methanol, 1.6 equivalent of dimethyl carbonate was obtained according to GC analysis. No dimethyl carbonate was observed in the absence of hydrogen chloride. Therefore, in the early stage of the carbonylation of 3, Pd/C is partly oxidized to palladium chloride (eqn. 2). This compound reacts in turn with CO and MeOH to give, according to one of the routes described in Scheme 2, dimethyl carbonate and a zerovalent palladium complex (noted [Pd]). 

Diazocine 8 was found to form complexes very slowly or not at all with palladium chloride or silver nitrate. ( )-Azobenzene behaved similarly, and since both compounds have similar pXa values, the ease of complex... 

Palladium-Catalyzed Conjugate Reduction of a,s-Unsaturated Carbonyl Compounds with Diphenylsilane and Zinc Chloride Cocatalyst a,B-Dihydro-B-Ionone... 

The elegant asymmetrization methodology of a meso compound, achieved in high enantioexcess under chiral environment, was the highlight of the total synthesis of (+)-pancratistatin (94) reported by Trost and Pulley (31]. The synthesis commenced with ( )-conduritol-A (130), obtained from p-benzoquinone, (Scheme 18) which was converted into the acetonide 131 and thence, via the dialkoxide to the cis-bis carbonate 132 (Scheme 19). The chiral n-ailyl palladium complex A formed on treatment erf 132 with the catalyst generated from chiral bis-amide 133 and n-allyl palladium chloride underwent azide substitution from the less hindered face of the molecule to provide the monocarbonate 134 in excellent yield and with high optical induction. 

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