Allyl maleimide

The effect of increased x-ray absorption on sensitivity was explored by conducting monochromatic exposures of a bromine-containing resist, poly(N-allyl maleimide-vinyl benzyl bromide), at photon energies which bracket the bromine absorption edges between 1.6 and 1.8 keV contrast curves obtained for these monochromatic exposures are shown in Figure 7. The results are also plotted as l/D "5 vs absorption coefficient in Figure 8 the data accurately follow the predicted inverse relationship defined by Equation 1. 

The most promising resist materials identified in this study aure copolymers of N-allyl maleimide with halogenated styrenes of these, P(MI-DiBrS) provided the best combination of speed, Dg 5 =... 

Alternating copolymers of N-allyl maleimide with a substituted styrene are promising negative working x-rav resists. These materials have sensitivities of 10-50 mJ/cm, providing a contrast of 1.5 or better, and appear capable of at least 0.5 m resolution. Further improvements in resist performance should be possible by optimization of polymer Mw and development conditions. 

Another original approach is exemplified by Ciba-Geigy s XU292. BMI is mixed with o,o -diallylbisphenol A (DAP, 2,2-bis(3-allyl-4-hydroxyphenyl)pro-pane Fig. 9) followed by heating to 110-125°C to obtain a liquid pre-polymer. The pre-polymer could be cured in the same way as common maleimide and epoxy resins are done [ 16,17]. 

Differently substituted pyrrolopyrroles can be constructed from a 1,3-dipolar cycloaddition, between the adduct from glycines and aldehydes and maleimides. Then, for example, the initially formed iV-allyl-o-bromophenyl-substituted pyrrolopyrrole mixture, 223, + 224, can then undergo an intramolecular cyclization in the presence of catalytic palladium(O) to give the pyrroloindolizine 225 <1991TL1359> (Scheme 61). 

Recently, two new axially chiral compounds 44 and 45 have been prepared [44, A-acryl-A-allyl-o-t-butylanilide 45, A-(o-t-butylphenyl)-2-methyl-maleimide]. This represents the first instance of using nonbiaryl axially chiral ligands in asymmetric Dield-Alder reactions. In the presence of iodine, high endo-facial and diastereofacial selectivities have been obtained in 44/45-medi-ated reactions.10... 

A variety of alternating copolymers based on H-allyl- and N-(3-ethynylphenyl)maleimides, with substituted styrenes and vinyl ethers, have been prepared and their response to x-ray irradiation studied. Broadband and monochromatic x-ray exposures were conducted at the Stanford Synchrotron Radiation Laboratory. Sensitivities were observed to correlate with mass absorption coefficients of the copolymers and were found to be as high as 5-10 mJ/cm2. Preliminary fine line lithographic studies indicate 0.5 ion resolution capabilities. 

As expected, the incorporation of pendant unsaturation in the resists greatly enhances sensitivity as demonstrated by a comparison of the contrast curves for poly(N-aiiyl maleimide-VBC) and the structurally similar poiy(N-ethyl maleimide-VBC) (Figure 4). Both polymers have similar molecular weights and nearly identical mass absorption coefficients but the allyl-containing copolymer is 5X faster. 

Allvl Maleimide—Allyl maleamic acid (50 gj 0.3326 mol) was melted at 125°C, poured into a 100 mL round bottom flask and distilled under reduced pressure to yield 17.8 g (39% of theory) of a colorless liquid which crystallized in the receiving flask as a white solid, m.p. 41-44°C (Lit. m.p. 42-44°C) (12). 

Intermolecular Allylboration. A tandem aza[4+2] cycloaddition/allyl-boration three-component reaction has been designed based on the prece-dented carbocyclic [4- -2] cycloaddition/allylboration and a snbsequent one-pot variant. Thns, the thermal reaction between hydrazonobutadienes 138, A-substitnted maleimides, and aldehydes provides polysnbstituted a-hydroxy-alkylpiperidines 141 via the cyclic allylboronate intermediate 139 and the proposed chairlike transition stmctnre 140 (Eq. 103). Monoactivated dienophiles like acrylates fail to react with heterodienes 138 bnt the scope of aldehydes is very broad both ahphatic and aromatic aldehydes are snitable, inclnding electron-rich ones. An inverse electron-demand variant to access the corresponding dihy-dropyran derivatives via the intermediacy of enantiomerically enriched pyranyl allylic boronate 76 has been snbsequently developed (see Eq. 64). ° ... 

The mechanism of the cross-link promotion of maleimides is assumed to be based on copolymerization of the polymer via its unsaturations with the maleimide molecules initiated by radicals, and in particular, by allylic radicals produced during the radiolysis of the polymer. ... 

The cross-linking rate of EPR by radiation comes close to that of polypropylene. EPDM terpolymers exhibit an enhanced cross-linking rate, and it increases with the diene content. However, not only the cross-linking rate, but also a greater yield of scissions results from the addition of the third monomer. Cross-linking of EPR can be promoted by the addition of a variety of additives, particularly by those that were found effective in polypropylene. Tetravinyl silane, chlorobenzene, nitrous oxide, allyl acrylate, neopentyl chloride, and N-phenyl maleimide were reported to promote the process. 

Wamhoff and Hupe [78] have irradiated 3,4-dibromo-A-methylmaleimide in benzene in the presence and in the absence of a sensitizer (X < or >313 nm). A mixture of products was formed in which two compounds were detected that had the skeleton of the primary ortho adduct. One of these products had been formed from the primary adduct by the addition of bromine at one of the double bonds of the diene moiety. The second compound had undergone further bromination at the allylic position in the six-membered ring. The photodimer of 3,4-dibromo-A-methylmaleimide, which was also formed, was considered to be the source of the bromine. This is one of the rare instances in which the primary 1 1 adduct of benzene and a maleimide derivative could be isolated, albeit in brominated form. 

In the same study, maleimides were irradiated in the presence of allyl alcohol and allyl ethyl ether, yielding the respective cyclobutanes with significant exo-preference [115]. Diastereofadal stereocontrol was achieved in the [2 + 2]-photo-cycloaddition of tetrahydrophthalimide by a chiral tether. The valinol-derived sub-... 

Pradilla et al. [140] have recently produced a nice paper showing that enan-tiopure hydroxy 2-p-tolylsulfinyl butadienes 158 (Scheme 78) undergo a highly face-selective Diels-Alder cycloaddition with AT-phenyl maleimide and phenyl-triazolidine dione, presumably controlled by the chiral sulfur atom (dienophile approach from the upper face of diene). Complementary 7r-facial selectivity (dienophile approach from the bottom face of diene) is displayed by related enantiopure sulfonyldienes 158 (Scheme 78). The authors suggest that the behavior of 158 is a consequence of the predominant influence of the chiral sulfur with respect to the hydroxylic carbon (the only chiral center in 158 ) on the stereochemical course of the cycloadditions. According to their explanation, dienes will adopt conformations similar to those depicted in Scheme 78, with the chiral centers employing their stereochemistry to maximum effect due to 1,3-allylic strain (which is considered as the main directing effect of these cycload-... 

Alkoxy-l-boronobutadiene reacted with maleimides, acrylates, and acrylamides to provide cyclic allyl boronates which undergo allylboration with aldehydes (Equation (148)).409 Analogous syntheses of cyclic allylboron compounds via [2+4]-cycloaddition is discussed in Section 9.05.2.2.1. 

The 6/3-NHCOCH=CHCOMe(f) and 6/3-NHCOCCl=CH2(f) analogs were more potent than /3-FNA as irreversible antagonists of GPI /x-sites (k-sites were little affected) while the highly reactive maleimides (6b and 6c) were much less effective in this respect. The N-allyl analog of /3-FNA was... 

The allylic ether monomer I has also been copolymerized with 7V-aryl maleimides, but in this case the tin loading is quite low (0.5 mmol g ) and the polymer appears to be less stable, especially at higher temperature. ... 

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