AUyl acetal

AUyl acetate can be obtained by the vapoi-phase reaction of propylene and acetic acid over a supported Pd catalyst (eq. 20) (110). Reaction of acrylic acid and propylene yields isopropyl acrylate (eq. 21), and catalytic reaction with acetic acid produces isopropyl acetate (eq. 22) (110). 

From a, bis(triehloromethyled) telogens, we carried out various telomerizations with methyl undeeylenate [59], ethylene [60], vinyl acetate [61] aUyl acetate [62-63], and with acrylates [61, 64]. We can notice that the aJlyl and acrylic derivatives lead to a mixture made of monoacetate and diadduct [63] ... 

Coupling reactions. The [(cod)lrCl]2 BINAP specimen transforms aUyl acetate into a TT-allyliridium complex. Reaction with a primary alcohol or an aldehyde affords homoaUyUc alcohol in chiral form. ... 

Two complementary methods for allylation of arene derivatives are Suzuki coupling with aUyl acetates, and converting allyl acetates to aUylindium reagents in situ for couping with ArX. ... 

Unmodified rhodium catalysts are readily formed in seCOa from simple precursor complexes such as [(CO)2Rh(acac)j, [(cod)Rh(hfacac)], or [Rh( (CO)i6] [33. The resulting rhodium carbonyl species are highly active in this medium for a range of substrates including simple olefins, vinyl arenes and polar substrates such as aUyl acetate. Especially the reaction rates for internal C=C bonds are remarkably higher than those observed in liquid organic solvents under typical hydroformylation conditions (Scheme 12.13). 

Allyl Acetate. Industrial production of aUyl acetate started only rather recendy. Nevertheless, among the aUyl compounds, its production is second to that of aUyl chloride. It is produced mostiy for manufacturing aHyl alcohol and its manufacture by acetoxylation of propylene has been described previously. The aUyl acetate obtained may be separated and purified by distillation. 

AUyl acetate [591-87-7] M 100.1, b 103 , d 0.928, n 1.4004, n 1.4040. The ester is freed from peroxides by standing with crystalline ferrous ammonium sulfate, then washed with 5% NaHCOs, followed by saturated CaCl2 solution. Dry it with Na2S04 and fractionally distil it in an all-glass apparatus. FLAMMABLE LIQUID. [Beilstein 2 H 136, 2IV 180.]... 

Oi, Inoue and coworkers developed a regioselective ruthenium-catalyzed direct arylation of aUyl acetate (101) using a catalytic system comprising [RuCl2(cod)]n and PPhs, giving rise to aUcenes 102 and 103 (Scheme 9.36) [49]. 

The first direct addition of a nucleophihc allylpalladium complex to aldehydes was published in 1996 by Yamamoto et al. [139]. Later on, Wallner and Szabo [7c, 140] have reexamined the regio- and stereoselectivities of the reaction employing density functional theory (DFT) computations. The intermediate it-allylpalladium complex 122 is generated by the reaction of an aUyl acetate (or chloride) 121 with hexamethylditin in the presence of allylpalladium chloride dimer (Scheme 12.58). The bis-aUylic system thus generated can then transfer a nucleophilic allyl fragment to the aldehyde 123. The reaction of bis-allylpalladium reagents generally yields branched homoallyUc alcohols 124 with prevalent anti diastereoselectivity. 

For a more complex example, refer to the H NMR spectrum of aUyl acetate (the NMR signal for the methyl group has been omitted) in Figure 8.24a. 

AUyl acetate, proton-proton coupling constants... 

Pd-catalyzed reactions of allylic esters such as aUyl acetates, carbonates, and phosphates with soft carbon nucleophiles such as malonate esters are useful for carbon-carbon bond formation (Sects. V.2.1.1-V.2.1.5). hi this section, Pd-catalyzed substitution reactions of nitrogen-containing allylic derivatives such as allylic amines, ammonium salts, tosylim-ides, and nitro compounds are described (Scheme 1). The allylic derivatives of other group 15 atoms have never been used as allyl unit source in Pd-catalyzed alkylation reactions so far. 

The direct, Pd(II)-catalyzed addition of heteroatom and stabilized carbon nucleophiles to alkenes is generally not a successful reaction. An exception is the addition of water, which gives carbonyl compounds and has been developed into an important indnstrial process, the Wacker process. This has been reviewed extensively.By contrast, the stoichiometric addition of nucleophiles such as amines is facile. - However, if alkenes could be converted catalytically into Tr-allylpalladium complexes, the problems with nucleophilic addition to alkenes could be circumvented and amines and other heteroatom nucleophiles could be employed. A range of alkenes have been converted into rr-allyl complexes in a stoichiometric fashion,t "t but catalytic reactions have proved more difficult. However, aUyl acetates and similar compounds readily exchange the acetate group for heteroatom nucleophiles in a Pd(0)-catalyzed reaction, which proceeds via 7T-allylpalladinm(ll) intermediates (Scheme 1). Since this reaction has been developed into a very important synthetic reaction, an efficient procedure for catalytic conversion of alkenes into aUyl acetates would have great synthetic potential. 

The stoichiometric addition of palladium acetate to alkenes has been studied extensively. (For a review, see Ref. [4].) For instance, 1-bntene was fonnd to give the vinyl acetate as the major prodnct, accompanied by small amonnts of the aUyl acetates - (Scheme 2). 

While it is evident that aUyhc acetoxylation and related reactions proceed via two different mechanisms, mainly depending on the structure of the alkenes, it is less clear how to choose reaction conditions in order to favor one route or the other. There is some evidence from early smdies that the use of polar solvents such as DMF will promote aUyl acetate formation. It also appears that excess acetate promotes the formation of products compatible with the rr-allyl route. This is also suggested by recent factorial experiments with variation of carboxylate concentration. Since trimeric palladium acetate will induce rr-allyl formation from a series of monoolefins, it might be assumed that high concentration of palladium acetate could be used for creating conditions that favor a 77-aUyl route. " Another possibility is adding strong acids, which can increase the electrophilicity of the catalyst, but this can drive the reaction toward homoallylic acetates and other isomerized products. "... 

A pyridinooxazoUne has been attached to polymeric supports, including TentaGel resin.f The supported ligand 83 has been employed to provide up to 80% ee in the standard reaction of aUyl acetate 4 with dimethylmalonate 5. 

Nonanoylzirconocene chloride (1), readily prepared by the reaction of 1-octene and zirconocene hydrochloride (Schwartz reagent) followed by exposure to 1 atm of CO, serves as an umnasked acyl anion and provides ketones or a-diketones in moderate to good yields by the reaction with electrophiles (aryl iodide, benzyl bromide, acyl chloride, allyl chloride, aUyl acetate) in the presence of 5% of PdCl2(PPh3)2 (Scheme 47). ... 

As shown in Scheme 5, the carbonylation of 3-(3-pyrrolyl)aUyl acetate (1) afforded compound 3 in addition to the expected product 2. The formation of 3 is explained by the... 

Starting from oxygen-linked 1,3-dicarbonyl compounds (malonates or acetoacetates), Tietze and co-workers have demonstrated an allylic substitution at the a-position of varions snbstrates (aUyl acetates, carbonates, and chlorides). Under the conditions employed, bisalkylation was observed in all cases. Since the acetoacetates could be alkylated by hard electrophiles at the y-position, a broad spectrum of compounds might be obtained. The cleavage from the resin was performed using DIBAL-H to obtain the corresponding diols (Scheme 24). 

More recently, allylic carbonates 115 have been found to conple with alkenylfluo-rosilanes in the presence of a paUadinm catalyst to yield the corresponding 1,4-dienes (equation 93). The corresponding palladium-catalyzed reaction of allylsilane with aUyl acetate 116 has been explored (eqnation 94). ... 

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