Itaconate esters

The efficiency of the new ligands was examined in enantioselective hydrogenation of some prochiral substrates. Itaconic ester hydrogenation using in situ prepared Rh-complexes was the first test reaction chosen. The best results from... 

In the hydrogenation of 3-substituted itaconate ester derivatives by rhodium-dipamp, the alkoxycarbonyl group at the stereogenic center also exerts a powerful directing effect, comparable to that induced by OH in the kinetic resolution of (a-hydroxyethyl)acrylate, leading to a high enantiomer-discriminating ability up to feR fes = 16 1 (Table 21.18, entry 5) [64]. 

Stereoselective hydrogenation of 3-substituted itaconate esters. Hydrogenation of the dimethyl itaconates (5) catalyzed by 1 results in. vyn-dialkylsuccinates... 

Copolymers of itaconic esters with butadiene have not yet been used technically. On the other hand, acrylonitrile containing copolymers with other components have been studied from several points of view. Standard Oil Co. has claimed a terpolymer of isobutylene, butadiene, and acrylonitrile, and BASF a similar product of butadiene, acrylonitrile, and styrene. The films from these combinations are said to have high flexibility and cold resistance. However, all butadiene containing copolymers are not light fast. Copolymers of butadiene, acrylonitrile, and unsaturated dicarboxylic esters are suggested for plasticizing PVC, but they must be thermally degraded before they are combined with the polymer. 

Walphos (138), developed by Sturm at the University of Vienna and optimized at Solvias, is derived from the Ugi amine 54.174175 Walphos can be electronically fine-tuned as various phosphine groups are introduced in separate steps of the synthesis. Walphos catalysts have been used to reduce enamide esters to a-amino esters, P-keto esters, a,P-unsaturated carboxylic acids, and itaconate esters with enantioselectivities >90%.176... 

By heating the pyrazolone formed by the addition of d azoacetic ester to itaconic ester a tribasic cyclopropane acid of the following formula results OHa - 0.- CHs-COOH. No X / COQH UH-COCH... 

As with cyclic alkenes, nonhydroxylic directing groups can be used in the directed hydrogenation of acyclic alkenes. The selective reductions of 3-substituted itaconate esters illustrate the directing capacity of esters (Table 5). It appears that the presence of coordinating allylic substituents can effect the level of selectivity. ... 

The acid and esters do not isomerize in solvents in the absence of strong adds or bases at temperatures up to 100° or higher. Isomerization of the itaconates through basic abstraction of a proton from the a-methylenic position might be ejq>ected to cause difficulty in anionic polymerization. In fact, attempts to polymerize itaconic esters (7) and amides (6) anionically have given little or no polymar, but considerable isomerization. 

Chinchilla, R., Galindo, N., and Najera, C., Dimethyl 2-(tosylmethyl)fumarate. An allyl sulfone as electrophilic reagent for the synthesis of itaconate ester derivatives. Tetrahedron, 52, 1035, 1996. 

In addition to enamides, other substrates can be reduced by the catalyst system, including enol acetates of a-keto acids and esters and itaconic esters and acids. 

Appropriate substrate-catalyst matching can achieve interesting enantiomer recognition. Chemical kinetic resolution is observed during hydrogenation of 3-substituted itaconate esters with Rh-dipamp catalysts , and of various prochiral secondary alcohols with binap . 

Hydrogenation. For an effective asymmetric hydrogenation of itaconic esters, the heterocomplex with Rh(I) center associated with two BINOL-derived phosphites of opposite electron-richness (lA, IB) emerges as a more active and selective catalyst. Also having been examined are 2 and the one bearing a carboranyl residue. ... 

Substitutions. Enolates generated from methyl ketones on treatment with LDA attack dimethyl 2-bromomethylfumarate in an Sn2 fashion, to give substitued itaconic esters. ... 

A general approach to itaconic esters is via the a-dimethylaminomethyl-succinates, which are formed by alkylation of )3-dimethylaminopropionic esters with a bromoacetate. 

Figure 4-13. Dependence of the hindrance parameter a on the formula molecular weight for a series of poly(methacrylic esters) -fCH2—CCH3(COOR) (O), and poly(itaconic esters) -FCH2—C(C00R)(CH2C00R) ( ) in toluene solution at 25 C (after J. Velickovic and S. Vasovi ).

The key intermediate, a cyclic hydrogenphosphinate, 9,10-dihydro-9-oxa-lO-phosphaphenanthrene-lO-oxide, has been converted, originally by Japanese manufacturers, to a variety of difunctional polymer intermediates. Addition to itaconic ester produces a dicarboxylic ester commercially used to make thermoplastic polyesters. This technology is discussed below in connection with modified polyester fibers and epoxy resins. Addition of the hydrogen phosphonate to itaconic acid and copolyesterification can be done in a single operation (61). 

This ring system has been used in epoxy resins as well as in thermoplastic polyesters. It has been the subject of many patents and publications, and is commercially produced in Europe and the Far East. Its original use was in Toyobo s flame-retardant polyester fiber, in the form of the itaconic ester adduct. 

Interestingly, itaconate esters can be polymerized at a moderate rate to yield high-molecular-weight polymers in spite of their possession of two bulky substituents. Kamachi et al. observed a 5-line ESR spectrum with small shoulders as shown in Fig. 61 when di-butyl itaconate (DBI) was photopolymerized in bulk with BP at low temperature. They computer-simulated a similar spectrum by assuming the hyperfine splitting constant to be 14.1 G for two P-protons and 10.1 G for another two P-protons, and concluded that the observed spectrum can be attributed to... 

Essentially the same results were later obtained with various prochi-ral substrates a-dehydro amino acids, enamides, - P-dehydroamino acid, unsaturated phosphonate, ° and itaconic ester. All studied substrates reacted instantaneously with 28a, b at -100°C yielding high ee s of the hydrogenation products—either equal or comparable to the ee s observed in the corresponding catalytic reactions. - ... 

The incorporation of itaconic acid and itaconic esters into PMMA-based copolymers has yielded polymers with significantly higher values with enhanced sensitivities. For example, copolymers of itaconic acid and (11) have been shown to have values five times those of PMMA with... 

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