Bornenes

The next seven references are cited not because of the experimental procedures described but because they indicate diversification in the types of enamines prepared and studied. Both Paquette (25) and Kasper 26) have condensed 2,5-methylene-l,2,5,6-tetrahydrobenzaldehyde (5-nor-bornene-2-carboxyaldehyde) (2) with several cyclic and open-chain aliphatic secondary amines. Kasper studied the ratio of endo to exo aldehyde formed upon hydrolysis of these enamines and the dihydro enamines. Paquette investigated the addition of sulfene to the enamines. -Fluoro-... 

Tile photolysis (A = 365 nm) of 42 alone resulted in a very slow conversion to the 1,4-dithiin 259, whereas the irradiation in the presence of nor-bornene quickly produced 260 in 95% yield (88CL657).Tlierefore, the conversion of 42 to 261 (or 262) and sulfur atom should be reversible. Tlie photolysis of 263 in 3-methylpentane at 77 K yielded a mixture of 261 and 262, as suggested by the electronic spectrum, which showed two absorption maxima at 580 and 370 nm (89TL2955). Similar results were also obtained for selenium species (88CL657 89TL2955). 

The kinetics of 1,3-dipolar cycloaddition of phenyl azide to nor-bornene in aqueous solutions was studied (Eq. 12.67).145 As shown in Table 12.1, when the reaction was performed in organic solvents, the reaction showed very small effects of the solvent, while in highly aqueous media, significant accelerations were observed. 

In terms of scope, activated alkenes beyond vinyl arenes, such as nor-bornene, couple effectively to aromatic and ,( >-unsaturated anhydrides, in-... 

In a recent study of intramolecular oxetane formation in naphthoylnor-bornenes Sauers and Rousseau provided evidence that two distinct excited states are involved<99) ... 

Tassin, A.-M., Maro, B. and Bornens, M. (1985) Fate of microtubule organizing centers during myogenesis in vitro. Journal of Cell Biology 100, 35-46. 

Intermolecular PKRs proceed especially easily with strained alkenes, e.g., nor-bornene, norbomadiene, and cyclobutene [97]. Nevertheless, highly strained MCP gave unsatisfactory results when reacted at 20 °C in hexane with acetylene, propyne, or phenylacetylene, both in terms of yields (10-15%) and of regioselec-tivity of the attack to the ethylenic bond (ca. 1 1) [100a, 103]. The reagents were consumed, but extensive tar formed and no variation in reaction conditions was successful. 

As had been observed in the synthesis of carbohydrate-substituted polymers of different lengths, the reactivity of the monomers was an important parameter in generating the triblock polymers. If the mannose-substituted 7-oxanor-bornene derivative was first polymerized, followed by the galactose-derivatized norbornene and the mannose-substituted norbornene monomers, two distinct sets of products were observed. These were identified by modification of the resulting polymers by acetylation, and analysis of the products by GPC. With this protocol, it was found that the product was composed of short polymers (DP=... 

Augustin A, Spenlehauer C, Dumond H, Menissier-De Murcia J, Piel M, Schmit AC, Apiou F, Vonesch JL, Kock M, Bornens M, De Murcia G (2003) PARP-3 locahzes preferentially to the daughter centriole and interferes with the Gl/S cell cycle progression. J Cell Sci 116 1551-1562... 

Moreover, alcohol functionalities have been introduced into the polynor-bornene (PNB) backbone by copolymerization of norbornene with a few percent of 5-acetate norbornene and subsequent acetate reduction. After transformation of the pendant hydroxyl functions into diethyl aluminum alkoxides, sCL has been ring opening polymerized (Scheme 31). Owing to the controlled/ liv-ing character of both polymerization processes the isolated poly(NB- -CL) graft copolymers were characterized by well-defined composition, controlled molecular weight and branching density, and narrow MWD (PDI=1.2-1.4) [92]. 

Cycloalkenes such as cyclohexene, 1-methylcyclohexene, cyclopentene, and nor-bornene are hydrosilylated with triethylsilane in the presence of aluminum chloride catalyst in methylene chloride at 0 °C or below to afford the corresponding hydrosilylated (triethylsilyl)cycloalkanes in 65-82% yields [Eq. (23)]. The reaction of 1-methylcyclohexene with triethylsilane at —20 °C occurs regio- and stereoselectively to give c/i-l-triethylsilyl-2-methylcyclohexane via a tra x-hydrosilylation pathway. Cycloalkenes having an alkyl group at the double-bonded carbon are more reactive than non-substituted compounds in Lewis acid-catalyzed hydrosilylations. ... 

Bailly E, Pines), Hunter T, Bornens M (1992) Cytoplasmic accumulation of cyclin B1 in human cells association with a detergent-resistant compartment and with the centrosome. J Cell Sd 101 529-545... 

Since the solvent is never completely removed at any time prior to final distillation of the product, the accumulation of higher boiling hydrocarbons results if petroleum ether is used. As a result the fore-run of the final distillation will be larger, and the yield of 2-bornene will be reduced. The pentane was distilled to assure the removal of any higher boiling impurities. 

When the temperature of the bath reaches 140-143°, the heating lamp is turned directly on the U-tube, and the receiver is changed to collect the 2-bornene. 

Bornene has been prepared from the reaction of 2-bromo-bornane-3-carboxyIic acid with aqueous sodium bicarbonate,6 by pyrolysis of isoborneol methyl xanthate,7 and by the j8-elimination of hydrogen chloride from bornyl chloride with sodium alkoxides in various solvents.2... 

Base-promoted tosylate elimination from (—)-bornyl tosylate is reported to yield bornene as the only hydrocarbon using potassium t-butoxide in DMF, in DMSO, and in benzene-(18-crown-6), although a second report of reaction in DMSO detects some camphene. ... 

The hetero-Diels-Alder reaction of homochiral camphor-derived thiabutadienes has given, for the first time, optically active bornene ring-fused dihydrothiopyrans with high diastereoselectivity (Scheme 53) <2000H(53)1685>. The exo endo- t2X o varied with the nature of substituent, varying from 91 9 (X = CH2, R = R = H) to 1 99 (X = CO,... 

In a well-ventilated hood, to a stirred solution of 4.7 gm (0.08 mole) of nor-bornene and 7.02 gm (0.06 mole) of isopentyl nitrite in 10 ml of ethanol, cooled to 0°C in an ice-salt bath, is added dropwise, over a hr period, a solution of 10 gm (0.59 mole) of 48 % hydrobromic acid in 12 ml of ethanol. After the addition has been completed, stirring in the ice bath is continued for another 20 min. The product is isolated by filtration and washed with ethanol. Yield 8.1 gm (80%), m.p. 134°-136°C. On recrystallization from chloroform, the melting point is raised to 138°-139°C. 

The ozonide of 2,3-diphenyl-2-bornene can be prepared by photosensitized addition of oxygen to the corresponding epoxide (313), as shown in equation 103. The structure of product 314 was determined by single-crystal XRD crystallographic analysis. It should be pointed out that both 302 and 314 have Oe envelope conformation for the 1,2,4-trioxolane... 

Cyclopentene and norbornene are highly flammable and harmful in contact with skin, eyes and the respiratory system. For poly(nor-bornene) no special hazards are reported. On handling, the usual precautions should be applied. 

A route of chemical recycling by pyrolysis has been examined (71). The pyrolysis of COC was performed in a fluidized-bed reactor. Various parameters, such as pyrolysis temperature, fluidizing gas or residence time were varied. Under favorite conditions, the undesired tar fraction could be reduced to a minimum of around 10%. Up to 44% of valuable gases and 45% of aromatic light oils could be obtained at a pyrolysis temperature of 700°C. In general, nor-bornene was recovered only in traces. Thus, it is concluded that 2-norbomene is not sufficiently stable to resist the conditions of pyrolysis. Actually, a retro-Alder reaction occurs resulting in ethene and cyclopentadiene. 

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