Norbomene derivatives

Lipase-catalyzed enantioselective transesterification of 0-substituted-l,2-diols is another practical route for the synthesis of P-blockers. Lipase PS suspended in toluene catalyzes the transesterification of (63) with vinyl acetate to give the (5)-ester in 43% yield and >98% ee (78). The desired product, optically pure (R)-ttitylglycidol, is then easily obtained by treating the ester with alcohoHc alkaU. Moreover, Pseudomonas Hpase catalyzes the acylation of oxazohdinone (64) with acetic anhydride in very good yield and selectivity (74). PPL-catalyzed transesterification of a number of /n j -norbomene derivatives proceeds in about 30% yield and 92% ee (79,80). 

A somewhat more complex application of this notion is represented by the CNS stimulant fencamfine (83). Diels-Alder addition of cyclopentadiene and nitrostyrene affords the norbomene derivative, 80. Catalytic hydrogenation reduces both the remaining double bond and the nitro group (81). ° Condensation with acetaldehyde gives the corresponding imine (82) a second reduction step completes the synthesis of fencamfine (83). ... 

Secondary orbital interactions (SOI) (Fig. 2) [5] between the non-reacting centers have been proposed to determine selectivities. For example, cyclopentadiene undergoes a cycloaddition reaction with acrolein 1 at 25 °C to give a norbomene derivative (Fig. 2a) [6]. The endo adduct (74.4%) was preferred over the exo adduct (25.6%). This endo selectivity has been interpreted in terms of the in-phase relation between the HOMO of the diene at the 2-position and the LUMO at the carbonyl carbon in the case of the endo approach (Fig. 2c). An unfavorable SOI (Fig. 2d) has also been reported for the cycloaddition of cyclopentadiene and acetylenic aldehyde 2 and its derivatives (Fig. 2b) [7-9]. The exo-TS has been proposed to be favored over the endo- IS. 

Norbomene derivatives are very popular monomers for ROMP due to a comparably high ring strain and good functionalisability. The latter is needed to append any desired functional unit to the monomer [98, 99]. 

Another example of this useful domino process is the enantioselective synthesis of the quinozilidine alkaloid (-)-lasubine II [234]. Condensed tricyclic compounds as 6/3-28 can also be prepared from norbomene derivatives 6/3-27 in excellent yield, as shown by Funel and coworkers (Scheme 6/3.6) [235]. 

In contrast to the behavior of 1,4-hexadiene and limonene, the regioselectivity of the norbomene derivatives 29 and 32 strongly depends on the catalyst. A... 

Gunter and co-workers have applied this methodology to the condensation of norbomene derivative 90 (block A, Scheme 32) with epoxide 94 (block B, Scheme 33) <98S593>. Thus, using the Crossley porphyrin-a-dione 47, condensation with 1,2,4,5-benzenetetramine tetrahydrochloride and then the product with a strained dione, gave 90 as block A. 

Not shown in Table I are several adducts obtained by cycloaddition of the acridizinium ion with 5,6-endo-substituted norbomene derivatives. These adducts each have two (imequally shielded) methylene hydrogen atoms which make simple the NMR analysis of mixtures of syn (8) and anti (9). When the 5,6-endo chain (R) was of the type... 

Since it is known that the cyclopentene ring of norbomene can be easily opened by methylidene carbene complex Ih, bicyclic compound 66 has been synthesized from norbomene derivative 65 having an alkene part in a sidechain in the presence... 

Electron transfer-induced nucleophilic addition to several otho cyclopropane compounds was also studied. The nucleophilic addition of methanol to quadricy-clane radical cation 8 produces the two methanol adducts 53 and 54. The stereochemistry of the methoxy groups in these structures identifies the preferred direction of nucleophilic attack upon the intermediate radical cations 8. Detailed NOE experiments delineate the structure of 53 and establish conclusively that the norbomene derivative 54 contains a 7-fl ri-methoxy group. The stereochemistry of both is compatible with stereospecific nucleophilic attack exclusively firom the exo-position. 7-Methylenequadricyclane also is attacked exclusively from the exo-face.These results can be explained via backside attack with inversion of configuration. 

Spater demonstrierten Sauers, Schinski und Mason 47), daB direkte Anregung der verschiedensten Norbomen-Derivate (71) in verdiinnten (0,1—2%) aprotischen Losungsmitteln, wie Aceton, Ather, Cyclohexan und Trimethylpentan oder Mischungen dieser Substanzen, in 16- 5%iger Ausbeute zu den korrespondierenden Norboman-Derivaten (72) fiihrt (Typ-B-Reaktion). 

Hydrates of RUCI3, IrCl3, and OSCI3 are suitable catalysts for the ROMP of norbomene in aqueous and alcoholic solvents. Ruthenium trichloride hydrate is used for the industrial production of poly(norbornene). These hydrates act for the ROMP of norbomene and norbomene derivatives in pure water through an emulsion process (18). 

N. Miyaki, Y. Miyamoto, S. Fukuhara, and T. Ootsuki, Norbomene derivative and norbomene polymer obtained therefrom through ring opening polymerization, US Patent 6 846 890, assigned to JSR Corporation (Tokyo, JP), January 25, 2005. 

Crosslinkable COCs are obtained by the modification with an alkoxysilyl group (2,47). A series of more or less complicated silyl modified norbomene derivates have been described (48). As a side effect, the silyl group improves the adhesion properties of the materials. 

T. Hasan, T. Ikeda, and T. Shiono, Homo- and copolymerization of norbomene derivatives with ethene by ansa-fluorenylamidodimeth-yltitanium activated with methylaluminoxane,. Polym. Sci., Part A Polym. Chem., 45(20) 4581-4587, October 2007. 

G.M. Benedikt, E. Elce, B.L. Goodall, H.A. Kalamarides, L.H. McIntosh, L.F. Rhodes, K. Selvy, C. Andes, K. Oyler, and A. Sen, Copolymerization of ethene with norbomene derivatives using neutral nickel catalysts, Macromolecules, 35(24) 8978-8988, November 2002. 

J.P. Mathew, A. Reinmuth, J. Melia, N. Swords, and W. Risse, (ry-3-allyl) palladium (ii) and palladium (ii) nitrile catalysts for the addition polymerization of norbomene derivatives with functional groups, Macromolecules, 29(8) 2755-2763,1996. 

D. Horton andT. Usui, Transformations of unsaturated acyclic sugars into enantiomerically pure norbomene derivatives, Carbohydr. Res. 216 33 (1991). 

Due to its versatile applicability, the CuOTf-catalyzed [2 + 2] photocycloaddition was used successfully to study the topology of the intermolecular and intramolecular dimerization of norbomene derivates. When a racemic mixture of compound 27 is transformed in the presence of CuOTf, a 1 1 mixture of two stereoisomers (28a,b) is... 

Partially hydrogenated polymers derived from norbomene derivatives, [1], prepared by Miyaki [2] were low in birefringence, high in wavelength dependency birefringence, and excellent in transparency and heat resistance. Additional functionalized norbomene derivatives were prepared by Liaw [3],... 

The living ROMP reactions of norbomene and norbomene derivatives have been used to make a variety of polymers possessing unusual properties. Copolymerization of selected fimctionalized norbomenes with norbomene has been used to synthesize star polymers and side-chain liquid crystal polymers. This chemistry has also resulted in the preparation of phase separated block copolymers that contain uniform sized metal or semiconductor nanoparticles. The... 

Other Pd Derivatives and Related Reactions. Other chiral palladium complexes, such as (DIOP)2Pd° or (DIOP)(alkene)Pd°, can be prepared from (DIOP)PdCl2. These catalysts have afforded low levels of asymmetric induction (10% ee) in the hydro-cyanation of norbomene derivatives. ... 

There are also several reports of enantioselective transesterification involving primary alcohols possessing stereogenic centers by similar acylation procedures, such as 2,3-epoxy alcohols (eq 7), norbomene-derived iodolactones, and 1,3-propanediols. ... 

Cross-metathesis of trialkoxy- and trisiloxy-substituted vinylsilanes [21] as well as octavinylsilsesquioxane [15] with vinyl sulfides proceeds efficiently but only in the presence of the 2nd generation Grubbs catalysts (IV) to offer a new and very attractive route for syntheses of [alkyl(aiyl)]sulfide-substituted vinylsilanes and vinyl-silsesquioxane with high preference for the -isomer, as illustrated by exclusive isolation of such isomers. The Fischer-type ruthenium carbene complex Ru(=CHSPh)Cl2(PCy3)2 has recently been reported as an effective catalyst in the ring opening/cross-metathesis of norbomene derivatives with vinyl sulfide [22], suggesting that these carbenes can be reactive in the cross-metathesis. 

Some thermosets are made with maleic anhydride only, or with other unsaturated 1,2-dicarboxylic acids or anhydrides such as itaconic acid or methylenesuccinic acid [7], chlorendic acid or 1,4.5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid (or anhydride), 1,4.5,6,7-pentachloro-5-norbornene-2,3-dicarboxylic acid anhydride or 1,4.5,6-tetrachloro-5-norbornene-2,3-dicarboxylic acid anhydride. These norbomene derivatives can be obtained from the Diels-Alder condensation of the chlorinated cyclopenta-1,3-dienes and maleic anhydride, as shown in the following reaction ... 

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