Norbomene carboxylate

Duvcor 385 Promerus (18) tert-Butyl norbomene-carboxylate-norbomene-5-methylenehexafluoro-isopropanol copolymer... 

As an example, when the photoacid generator triphenylsulfonium hexafluoro-antimonate is exposed to radiation, it decomposes to release the superacid hexafluoroantimonic acid in the resist film. While this photochemical reaction can occur at room temperature, the acid-catalyzed deprotection of the pendant t-butyl group of the resist polymer occurs at reasonable rates only at elevated temperature. It is therefore necessary to heat the resist film to an appropriate temperature (PEB) to provide the energy that is required for the acid-catalyzed deprotection of the t-butyl group of the ester, which in mrn affords the base-soluble norbomene carboxylic acid unit the isobutylene volatilizes. The extent of deprotection at constant temperamre is dependent on the dose of applied radiation. By monitoring the carboxylic acid OH stretch 3000-3600 cm and the ester carbonyl (C O) around 1735 cm acid carbonyl (C O) around 1705 cm , and ester (C-O-C) stretch around 1150 cm it is possible to determine by means of IR spectroscopy the extent of dose-dependent deprotection, as well as the influence of baking temperature on the extent of deprotection for each resist system. Doses ranging from 0 to 50 mJ/cm were applied to each resist system, after which they were baked at 120, 130, 140, and 150°C for 60 seconds and analyzed by FTIR. ... 

When the photoacid generator, triphenylsulfonium hexafluoroantimonate, is exposed to radiation, it decomposes to release the super acid, hexafluoroantimonic acid, in the resist film. While this photochemical reaction can occur at room temperature, the acid-catalyzed deprotection of the pendant r-butyl group of the resist polymer occurs at reasonable rates only at elevated temperature. It is therefore necessary to heat the resist film to an appropriate temperature (postexposure bake) to provide the energy that is required for the acid-catalyzed deprotection of the r-butyl group of the ester, which in turn, affords the base-soluble norbomene carboxylic acid unit isobutylene volatilizes. The extent of deprotection at constant temperature is... 

Kaita Sh, Matsushita K, Tobita M, Maruyama Y, Wakatsuki Y (2006) Cyclopentadienyl nickel and palladium complexes/activator system for the vinyl-type copolymerization of norbomene with norbomene carboxylic acid esters control of polymer solubility and glass transition temperature. Macromol Rapid Commun 27 1752-1756... 

Figure 29 Proposed 2/1 dimer structure formed by the reaction of TIBA and norbomene carboxylic acid.

Figure 8.16 Conversion of e Jo-5-norbomene-2-carbonitrile to the corresponding carboxylic acid using Alcaligenes faecalis Nit338...

In a similar way, norbomene 2-ethylhexyl carboxylate, nor-bomene isobornyl carboxylate, norbomene phenoxyethyl carboxylate, (5) are and related monomers are obtained. As catalysts, osmium or ruthenium catalysts similar to those shown in Figure 1.8 are used. 

Carboxylic esters of norbomene can be polymerized with Pd-(Il)-nitrile catalysts Pd(RCN)4 x (BF4)2 with R = CH3,C2H5 (39). However, the polymerization takes place only selectively, as mostly the exo isomer polymerizes. 

Amphiphilic star-block copolymers can be prepared by adding a polycyclic diene such as 238 to a living diblock copolymer made by sequential ROMP of (i) the monomer in Table 9 with R = COOSiMe3, and (ii) norbomene. The trimethylsilyl ester groups are then converted to carboxylic acids by soaking the cast film of the polymer in water for 2-3 days to give a product with a hydrophobic core of polynorbomene and a hydrophilic outer layer126,502. 

Amino acid-based norbomene random and block copolymers have been synthesized by Sanda, Masuda et al. [178]. The blocks were constructed with monomers containing either the ester or carboxyl amino acid forms, and C4 was used. While the random copolymers were partially soluble in acetone, the block copolymers were soluble through formation of reverse micelles (Scheme 24). Moreover, the diameter of these aggregates was around 100 nm as measured by DLS and AFM. Amino acid-based ROMP monomers with a different cyclic core, i.e., cyclobutenecarbonyl glycine methyl esters, were polymerized by Sampson et al., leading to head-to-tail-ordered polymers without stereocenters [179]. C6 was used and polydispersities between 1.2 and 1.6 were obtained. 

Although a large number of chiral dienophiles have been developed (Table 26.2), their ability to provide high asymmetric induction appears to be limited to specific dienes. However, there are some dienophiles that tolerate a wider variety of dienes including menthol derivatives,117 118 camphor derivatives,6 39 40 105 107-113 181 182 and oxazolidinones.120 165 183 184 It should be noted that even these auxiliaries would require an efficient recycle protocol for economic scale up. One exception is the use of sacrificial chiral oxazolidinones, which are relatively inexpensive. This approach has been used in the large-scale preparation of the base cyclohexane unit of Ceralure Bj.168 A procedure has been developed for the preparation of (75,25)-5-norbomene-2-carboxylic acid where the D-panta-lactone auxiliary can be recycled efficiently.185186... 

Preparation of Poly(t-Butyl 5-Norbornene-2-Carboxylate-co-Carboxy-t-Butoxy Sultone Norbomene)... 

In a 100-ml crimped vial, t-butyl 5-norbomene-2-carboxylate (17.5 mmol) and the Step 1 product (7.5 mmol) were dissolved in 40 ml of toluene and then sparged with nitrogen for 30 minutes. The mixture was next treated with the slow addition of freshly prepared bis(toluene)bis(perfluoro-phenyl) nickel (II) catalyst (0.5 mmol) in 10 ml of dry toluene and stirred overnight. The polymer was precipitated into hexane and filtered, and 3.5 g of white powder were isolated. 

The concept of using an ester auxiliary which also contains a handle suitable for chelation was first disclosed in 1984/1985. Thus TiCU-promoted addition of cyclopentadiene to the acrylate of ethyl (S)-lactate (379) proceeded readily at -63 C to give (with a 39 1 endolexo preference) a 93 7 mixture of norbomenes (381a) and (382a), from which the major product (381a) was isolated by MPLC (Scheme 93, Table 23, entry 1). Mild saponification of adduct (381a) with LiOH in aqueous THF and purification via iodolactonization/elimination provided pure (l/ ,2/ )-5-norbomene-2-carboxylic acid. 

Protonolysis occurs with retention of stereochemistry at the carbon atom originally attached to boron.Thus, by use of a deuteriated hydroborating agent e.g. 9-BBN-D) or of a deuteriated carboxylic acid, or both, deuterium atoms can be introduced at specific and predictable locations in a molecule. An example is the conversion of 2-norbomene into ej o,ej o-2,3-dideuterionorbomane (equation 56). ... 

Gust, Moore, Moore and coworkers covalent cartenoid-porphyrin-quinone molecular triads 55-60 contain a cyclized hydrogen bond within the quinone acceptor framework [143], The naphthaquinone moiety of 55 is fused to a norbomene system whose bridgehead position bears a carboxylic acid, which can hydrogen bond to an adjacent quinone. Photoinduced electron transfer from the porphyrin to the quinone leads to a marked p/fg increase of the latter, resulting in a fast proton transfer ( pt 10 s ) to form the semiquinone. Back electron transfer from the semiquinone is attenuated as a consequence of the proton-stabilized charge-separated species. This leads to a two-fold increase in the quantum yield of the charge-separated state of 55, as compared to those of the reference triads 56 and 57 (see Volume III, Part 2, Chapter 2). 

Fascinating rearrangements of aziridines have been applied to the synthesis of diterpene alkaloids by Wiesner and co-workers (Scheme 40). For example, the ester 217, prepared from cyclopentadiene carboxylate (215) and the benzyne precursor 216 by a Diels-Alder reaction, was converted to the aziridine 218 by treatment with benzenesulfonyl azide in 83% yield. When the aziridine 218 was heated with water for 24 h, the hydroxy ester 219 was obtained in 97% yield subsequent oxidation with the Jones reagent afforded the ketone 220. This rearrangement is analogous to that of the benzenesulfonylaziridine of norbomene. ... 

Norbomyl-2-exo-carboxylic acid. For the preparation of this acid by the hydrocarboxylation of norbomene at 50°, see Nickel carbonyl. 

Addition of carboxylic acids to alkenes (e.g., norbomene) is promoted by FeCls-AgOTf in refluxing 1,2-dichloroethane. Unsaturated carboxylic acids give y-lactones. ... 

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