Ethyl acrylate, base-catalyzed

A tandem palladium catalyzed multi-component approach has been devised providing direct access to for instance trisubstituted thiophenes from the simple starting material 3-iodothiophene 41. In a representative experiment, the substrate 41 was converted to the product 42 by treatment with ethyl acrylate and iodobutane in the presence of a catalytic system consisting of Pd(OAc)2, tri(2-furyl)phosphine (TFP), norbomene, and a base. A mechanistic rationale accounting for this outcome was also proposed <06OL3939>. 

In a base-catalyzed substitution reaction with benzamide, ethyl 2-cyano-3,3-bis(methylsulfanyl)acrylate 280 gave the 3-aminoacrylate derivative 281, which on thermal cyclization yielded the functionalized 6-imino-l,3-oxazine 282 (Scheme 52) <1995BML695>. 

Synthetic approaches toward mitomycin analogs have prompted the preparations of many benzopyrrolizines.46 49 One involved base-catalyzed 1,4-addition of ethyl indole-2-carboxylates (67) to an acrylic ester, followed by... 

The asymmetric addition of glycine enolates to acrylates was also achieved by use of the tartaric acid-derived phase-transfer catalysts 27 and 28 (Scheme 4.9). Arai, Nishida and Tsuji [13] showed that the C2-symmetric ammonium cations 27a,b afford up to 77% ee when t-butyl acrylate is used as acceptor. The cations 28 are the most effective/selective PTC identified by broad variation of the substituents present on both the acetal moiety and nitrogen atoms [14], In this study by Shibasaki et al. enantiomeric excesses up to 82% were achieved by use of the catalyst 28a (Scheme 4.9) [14], Scheme 4.9 also shows the structure of the guanidine 29 prepared by Ma and Cheng in the absence of additional base this also catalyzes the Michael addition of the glycine derivative 22 to ethyl acrylate, albeit with modest ee of 30% [15],... 

The base-catalyzed cyclocondensation of methyl acrylate with ethyl... 

Another method is based on the metal-catalyzed polymerization from carbon—halogen bonds in the main-chain units, which was applied for the synthesis of C-3 and C-4.430 For C-3, the main chain polymers with controlled molecular weights were prepared via the copper-catalyzed radical polymerization of tri-methylsilyl-protected HEMA followed by the transformation of the silyloxyl group into 2-bromoisobu-tyrate. The pendant C—Br bonds were subsequently activated by the copper catalysts to polymerize styrene and nBA. A more direct way is employed for C-4 i.e., via conventional radical polymerization of 2-[(2-bromopropinonyl)oxy]ethyl acrylate followed by the copper-catalyzed graft polymerization of styrene and nBA from the C—Br substituent. 

With other metal alkoxides, such as n(Ot-Pr)4 and Sn (Oi-Pr)4, Ru-1 induced faster polymerizations of MMA than Al(Ot-Pr)3, though the MWDs became slightly broader. Aluminum acetylacetonate [Al(acac)3] was a mild alternative additive that did not induce an ester-exchange reaction between the ester group and the monomer or monomer units in the polymer chain, which might occur using aluminum alkoxides. These metal alkoxides were also effective for other metal complexes, such as iron, nickel, rhenium, and copper. " It is noteworthy that Al(Oi-Pr)3 could even make the Cu(II) species active, in which the controlled polymerizations of styrene, MMA, and ethyl acrylate were possible." " Ti(Oi-Pr)4 was also efficient for the half-metallocene Fe(II)-catalyzed polymerizations, as will be mentioned in Seaion 3.13.3.1.2." Based on calculation studies by Poli et the nature of Al(Oi-Pr)3 in the... 

The catalytic performance of NHC-Pd complexes in this reaction is however usually less satisfactory than that of catalytic systems based on other ligands, such as, for example, phosphane hgands, and poly-NHC Pd complexes make no exception to this general trend. Consequently, although reports on the catalysis of the Heck reactions by these complexes have been numerous, they are often hmited to the reaction of aryl iodide or electron-poor, activated aryl bromide substrates, whereas electron-neutral or electron-rich aryl bromides require high temperatures for satisfactory yields. Reactivity of aryl chlorides is confined to electron-poor substrates and is observed only under very drastic conditions (T> 150 °C with tetra-alkylammonium salts as promoters). " An exception is represented by the work of Huynh and Guo on dipalladium(II) complexes with the Janus-type ditz ligand of structure 68." In this case, Heck reactions of activated aryl chlorides were possible already at 120 °C without addition of promoters the authors ascribe this result to the cooperative effect of the two metal centers. Poly-NHC complexes of type 69 have been found to catalyze also the less common diarylation (i.e., double Heck reaction) of ethyl acrylate with aryl bromides, albeit at 120 °C and with tetrabutylammonium bromide as additive. " Simple Pd species such as Pd(OAc)2 and PdCl2 were found to be quite ineffective under these conditions. 

In the first example of Figure 5.35, base-catalyzed reaction of two equivalents of aqueous H CHO with diethyl malonate furnished diethyl bis(hydroxy[ C]methyl)malonate 108. Concurrent bis-bromodehydroxylation, ester hydrolysis and decarboxylation of 108, followed by re-esterification and dehydrobromination provided ethyl 2-bromo[ C]-meth[3- C]acrylate 109, a key intermediate in the Reformatsky reaction with ketones, which give a-[ " C]methylene y- - C]butyrolactones 110. ... 

PTA was used as an organic base to catalyze Morita-Baylis-Hillman type reactions (Scheme 7.9) [49-51]. Variously substimted aryl aldehydes ArCHO were reacted with ethyl acrylate in THF/H2O (4 1, v/v) at room temperature in the presence of a catalytic amount of 1 (20 mol %) giving the addition products after 5-19 h in yields ranging from 59 to 93%. 

Direct, acid catalyzed esterification of acryhc acid is the main route for the manufacture of higher alkyl esters. The most important higher alkyl acrylate is 2-ethyIhexyi acrylate prepared from the available 0x0 alcohol 2-ethyl-1-hexanol (see Alcohols, higher aliphatic). The most common catalysts are sulfuric or toluenesulfonic acid and sulfonic acid functional cation-exchange resins. Solvents are used as entraining agents for the removal of water of reaction. The product is washed with base to remove unreacted acryhc acid and catalyst and then purified by distillation. The esters are obtained in 80—90% yield and in exceUent purity. 

A series of a-halopropionates (1-21 and 1-22, X = Cl, Br), model compounds of the dormant polymer terminal of acrylates, are suitable for not only acrylates but also styrenes and acrylamides. Ethyl 2-chlo-ropropionate (1-21, X = Cl) was employed for the controlled radical polymerizations of MA and styrene catalyzed by CuCl/L-1 to afford relatively narrow MWDs (MwIMn 1.5).84 A better controlled polymerization of MA is achieved with the bromides 1-21 and 1-22 (X = Br) in conjunction with CuBr/L-1 to give narrower MWDs (MJMn 1.2).84 A similar result was obtained with the combination of 1-23 and CuBr/L-1 for the polymerization of styrene.166 A nickel-based system with Ni-2 and 1-21 (X = Br) gave another controlled polymerization of nBA.134 The iodide compound 1-21 (X = I) is specifically effective in conjunction with an iodide complex such as Re-1 to induce controlled polymerization of styrene.141... 

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