Maleate dimethyl

Donor substituents on the vinyl group further enhance reactivity towards electrophilic dienophiles. Equations 8.6 and 8.7 illustrate the use of such functionalized vinylpyrroles in indole synthesis[2,3]. In both of these examples, the use of acetyleneic dienophiles leads to fully aromatic products. Evidently this must occur as the result of oxidation by atmospheric oxygen. With vinylpyrrole 8.6A, adducts were also isolated from dienophiles such as methyl acrylate, dimethyl maleate, dimethyl fumarate, acrolein, acrylonitrile, maleic anhydride, W-methylmaleimide and naphthoquinone. These tetrahydroindole adducts could be aromatized with DDQ, although the overall yields were modest[3]. 

Another impo2rtant P—C-hond-forming reaction is the base-cataly2ed Michael addition to activated double bonds. For example, dimethyl phosphite can be added to dimethyl maleate to yield tetramethylphosphonosucciaate [2788-26-3] (TMPS), an iatermediate ia the synthesis of 2-phosphonobutane-l,2,4-tricarboxyhc acid [37971-36-1] (PBTC) with 98% yield (20). 

Dimethyl succinate [106-65-0] (mp 19°C, bp 196°C at atmospheric pressure) can be produced from methanol and the anhydride or the acid, or by hydrogenation of dimethyl maleate (38,39). The same methods can be used to prepare diethyl succinate [123-25-1] (mp — 18°C, bp 216.5°C at atmospheric pressure) and diisopropyl succinate [924-88-9]. 

In a manner analogous to classic nitrile iinines, the additions of trifluoro-methylacetonitrile phenylimine occur regiospecifically with activated terminal alkenes but less selectively with alkynes [39], The nitnle imine reacts with both dimethyl fumarate and dimethyl maleate m moderate yields to give exclusively the trans product, presumably via epimenzation of the labile H at position 4 [40] (equation 42) The nitrile imine exhibits exo selectivities in its reactions with norbornene and norbornadiene, which are similar to those seen for the nitrile oxide [37], and even greater reactivity with enolates than that of the nitnle oxide [38, 41], Reactions of trifluoroacetomtrile phenyl imine with isocyanates, isothiocyanates, and carbodiimides are also reported [42]... 

Note Polyfhexamethylene maleate) can be synthesized according to the same procedure using dimethyl maleate instead of dimethyl fumarate. In this case, a mixture of linear chain (76% mass) and cychc species (24% mass) are obtained. 

Earle and coworkers [54] have performed Diels-Alder reactions in neutral ionic liquids. The results of reactions of cyclopentadiene with dimethyl maleate, ethyl acrylate and acrylonitrile are reported in Table 6.10. The cycloadditions proceeded at room temperature in all of the ionic liquids tested, except [BMIMJPF4, and gave almost quantitative yields after 18-24h. The endo/exo selectivity depends on dienophile. No enantioselectivity was observed in the [BMIM] lactate reaction. 

Table 6.10 Diels-Alder reactions of cyclopentadiene with dimethyl maleate, ethylacrylate and acrylonitrile in neutral ionic liquids...

The addition of various Kolbe radicals generated from acetic acid, monochloro-acetic acid, trichloroacetic acid, oxalic acid, methyl adipate and methyl glutarate to acceptors such as ethylene, propylene, fluoroolefins and dimethyl maleate is reported in ref. [213]. Also the influence of reaction conditions (current density, olefin-type, olefin concentration) on the product yield and product ratios is individually discussed therein. The mechanism of the addition to ethylene is deduced from the results of adsorption and rotating ring disc studies. The findings demonstrate that the Kolbe radicals react in the surface layer with adsorbed ethylene [229]. In the oxidation of acetate in the presence of 1-octene at platinum and graphite anodes, products that originate from intermediate radicals and cations are observed [230]. 

Pyrrolidines have been prepared by 1,3-dipolar cycloaddition of N-(benzyli-dene)trimethylsilylamine/TMSOf 20 and methyl acrylate, N-methylmaleimide, or dimethyl maleate [35]. More recently, methyl trans-3-cyanociruiamate 1479 was reacted with N-benzyl-N-(trimethylsilylmethyl)aminomethyl methyl ether 1480 and trifluoroacetic acid in CH2CI2 at 0°C and 24°C to afford, via 1481, the pyrrolidine derivative 1482 in high yield and MeOSiMe3 13a [35a] (Scheme 9.20). Several... 

Diels-Alder reactions are stereospecific with respect to the E- and Z-relationships in both the dienophile and the diene. For example, addition of dimethyl fumarate and dimethyl maleate with cyclopentadiene is completely stereospecific with respect to the cis or trans orientation of the ester substituents. 

The photocycloaddition of dimethyl maleate to norbomene yields cyclobutanes (91) and (92), while the photocycloaddition of maleic anhydride to this olefin yields (92) and (93) (after hydrolysis)<100> ... 

Similarly, the Pd-catalyzed arylation of l,3-dicyclopropyl-l,2-propadiene 6/1-122 with iodobenzene in the presence of dimethyl maleate led to the diastereomeric cyclopropane derivatives 6/1-124 and 6/1-125 via 6/1-123 in 86% yield as a 4 l-mix-ture [65] (Scheme 6/1.33). Several other aryl halides and dienophiles have been used in this reaction. 

Treatment of benzo[c][l,5]naphthyridine with dichlorocarbene, formed from the thermal decomposition of sodium trichloroacetate, gives the corresponding iV-dichloromethylide, 1,3-dipolar cycloaddition of which with DMAD, with loss of HC1, gives the corresponding pyrrolonaphthyridine 284 (Equation 98) <1995M227>. In the [1,6]- and [1,7]-naphthyridine series, compounds 285 and 286 are obtained by the same route and in the [l,8]naphthyridine series compound 287 is obtained from the parent naphthyridine, dichlorocarbene, and dimethyl maleate followed by oxidation (Equation 99) <1998RJ0712>. 

The polymerization of dimethyl maleate and 1,6-hexanediol proceeded using lipase CA catalyst in toluene to give the polymer exhibiting exclusively cis structure [55]. During the polymerization, cyclic oligomers were formed. The cycles were semi-crystalline, whereas the linear polymer was amorphous. In the lipase CA-catalyzed copolymerization of dimethyl maleate and dimethyl fumarate with 1,6-hexanediol, the content of the cyclization was found to depend mainly on the configuration and concentration of the monomers [56]. 

Of special significance concerning the reaction of Cp2Ti(CO)(PEt3) (41) with dimethyl maleate was the observation that the 40% molar excess of... 

Methyl diazoacetate is also decomposed on Raney nickel to give quantitatively a mixture of dimethyl fumarate and maleate 369) N2 evolution is observed even at room temperature. Most remarkably, dimethyl maleate is formed with high stereoselectivity (at 70 °C 92% of dimethyl maleate, 7% of dimethyl fumarate 370)). This represents one of the few cases of stereoselective synthesis on metal surfaces which have been found so far. 

It the solution of methyl diazoacetate is dropped through the condenser the diazo compound is further diluted by the refluxing solvent. This simple technique diminishes formation of dimethyl lumarate and dimethyl maleate as side products. 

Independent work by Schmid93 and by Padwa94 on the photochemistry of 2H-azirines has shown that irradiation of such systems leads in the first instance to the formation of nitrile ylids (nitrilium betaines). Subsequent 1,3-addition to a variety of dipolarophiles affords five-membered heterocycles. These additions take place in a stereospecific and regioselective manner thus, irradiation of the diphenyl-2f/-azirine 117 in the presence of dimethyl maleate leads to the formation of the two isomeric 1-pyrrolines... 

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