Allyl chloride palladium catalysis

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... 

Synthesis of isomeric chiral protected (63 )-6-amino-hexahydro-2,7-dioxopyrazolo[l,2- ]pyrazole-l-carboxylic acid 280 is shown in Scheme 36. Crude vinyl phosphonate 275, obtained by treatment of diethyl allyloxycarbonylmethyl-phosphonate with acetic anhydride and tetramethyl diaminomethane as a formaldehyde equivalent, was used in the Michael addition to chiral 4-(f-butoxycarbonylamino)pyrazolidin-3-one 272. The Michael addition is run in dichloro-methane followed by addition of f-butyl oxalyl chloride and 2 equiv of Huning s base in the same pot to provide 276 in 58% yield. The allyl ester is deprotected using palladium catalysis to give the corresponding acid 277, which is... 

We reported that the palladium-catalyzed reaction of arynes with bis-jr-allyl palladium complex afforded 1,2-diallylated derivatives of benzene in good yields (Scheme 32) [77]. The reaction of 104 with allyltributylstan-nane 3a and allyl chloride 11 in acetonitrile in the presence of 2.5 mol % Pd2(dba)3.CHCl3/dppf catalyst at 40 °C for 12 h afforded 1,2-diallyl benzene 105 in 76% yield. The generation of benzyne 106 takes place presumably first from 104 under the conditions of the palladium catalysis, which reacts with the complex 2 in a manner similar to the diallylation of activated olefins (refer Scheme 29). 

A counter phase transfer catalysis effect was observed in reduction of allyl chloride with sodium formate in water/n-heptane systems with water soluble palladium(II) catalysts having phosphine ligands with polyether chains [274] it was demonstrated that the catalyst transported the substrate to the aqueous phase where it reacted with the formate. 

Palladium is a useful catalyst in several reactions which lead to keto-esters. p-Keto-esters react with allylic carbonates, with catalysis by palladium, in a decarboxylative allylation reaction. y-Keto-esters are prepared, in reasonable yield, by the palladium-catalysed regioselective oxidation of Py-unsaturated esters. y-Keto-esters are obtained in good yield by the palladium-catalysed Reformatsky reaction of ethyl bromoacetate and acid chlorides. Derivatives of y-ketopimelic acid are formed by the rhodium-carbonyl-catalysed reaction of derivatives of acrylic acid with carbon monoxide. A mild method for the conversion of propiolic esters into P-keto-esters via thiol addition has been reported (Scheme 63) it has been used in a formal synthesis of ( )-thienamycin. 

The [2+2] cycloaddition of a ketene and an imine leading to P-lactams can be accomplished using palladium catalysis. Starting from an allyl phosphate or allyl chloride (see also 1), carbonylation with carbon monoxide lead to an intermediate ketene that cycloadds to imines to form the desired P-lactams (Scheme 5-176). ... 

Palladium(II) catalysis (0.01-0.04 equiv) is more effective and leads to higher selectivity than mercury(II) catalysis912. With bis(acetonitrile)palladium(II) chloride [Pd(CH3CN)2CI2] as catalyst the efficiency decreases in the order carbamates > allylic acetates > carbonates. 

Coupling of allyl bromides and aUylstannanes. This reaction is possible by catalysis with benzylchlorobis(triphenylphosphine)palladium, which is probably converted into bis(triphenylphosphine)palladium(0), the actual catalyst. This Pd(0) complex is more effective than tetrakis(triphenylphosphine)palladium(0). Zinc chloride in certain cases can function as a catalyst alone or in combination with the Pd(II) catalyst.1... 

Joint catalysis by tin(IV) chloride and zinc chloride induces coupling of the acetal 114 with the alkyne 115 to give the propargyl ether 116. Allyl halides condense with terminal alkynes in DMF in the presence of copper(I) iodide, potassium carbonate and tetrabutylammonium chloride under phase-transfer conditions to afford eneynes, e.g. equation 19. Palladium-catalysed coupling reactions of 1-bromoallenes with terminal acetylenes have been reported for the first time thus acetylene and the allenes 117 (R R = Me or Et) in triethylamine in the presence of tetrakis(triphenylphosphine)palladium and... 

Many examples of alkene and alkyne insertion into metal-carbon bonds can also be found in the section on homogeneous catalysis. Other recent examples include the insertion of conjugated dienes into palladium-allyl bonds, olefin arylation in the presence of palladium acetate, and the reaction of ethylene with arylmagnesium halides in the presence of nickel chloride. Reaction of isocyanates with nickel-ethynyl compounds... 

Couplings WS Allyl Intermediates- Excellent reviews cover selectivities and mechanism in palladium catalysed allyl reactions. General examples of NaCH(CX)2R)2 additions to allyl acetates, carbonates, and chlorides have appeared. Trifluotoacetale is the preferred leaving group for retention of (E)/( stereochemistry in the case of substituted allyls. Ketomalonates are susceptible to diallylation under PdL2 catalysis especially in the presence of diacetates whidi prove effective routes to bicyclic systems (Equation 6). ... 

Metalation-demetalation sequences have been invoked to account for palladium(u) chloride-catalysed allylic and enol ester exchange, and organomercury(ii) and bis(organo)thallium(iii) ion catalysis of the hydrolysis of isopropenyl acetate. 

Organozirconocene Chlorides. Acyl zirconocene chlorides function as efficient donors of acyl anions and can react with allylic or propargylic halides (X=Cl, Br, I, OTs) under Cul catalysis. In these reactions, acyl copper species (RCOCu), generated by the transfer of acyl group fromZr to Cu, were speculated to be the reactive species. These Cul-catalyzed reactions of acyl zirconocene chloride are cort5)lementary to the palladium-catalyzed reactions and enable the formation of -y-unsaturated ketones, which suffer ready isomerization under the palladium-catalyzed conditions (eq 23). On the other hand, carbonylative cross-coupling of F-o -selanylvinylzirconiums with alkynyUodonium tosylates can be performed in THF in the presence of 3 mol% of Cul and atmospheric pressure of carbon monoxide in a palladium-free system. 

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