Reaction Of Norbornene Research Articles

Organopalladium approaches to prostaglandins. : 6. synthesis of Interphenylene Prostaglandin Endoperoxidte Analogs Via Benzylpalladation of Bicyclic Alkenes.

The reactions of norbornene, norbornadiene and 7-oxanorbornene with methyl 3-(chloromethyl) phenoxyacetate (4), optically pure (S)-1-octyn-3-ol (5), and 8% Pd(PPh 3) 4 afford in one step satisfactory yields of the corresponding esters 6, 7 and 8 respectively, readily saponified to the first interphenylene prostaglandin endoperoxide analogs 10, 11 and 12 respectively.

ChemInform Abstract: Stereochemistry of Adding Ethyl Azidoformate to Bicyclic Olefins.

AbstractThe stereochemistry of the thermolytic ‐ method A) ‐ and the photolytic ‐ method B) ‐ reactions of norbornene (I), benzonorbornadiene (VI) and of 7‐isopropylidene‐benzo‐ norbornadiene (X) with ethyl azidoformate (II) are investigated.

ChemInform Abstract: Titanacyclobutanes Derived from Strained Cyclic Olefins: The Living Polymerization of Norbornene.

AbstractThe title compounds (II) are obtained from the reaction of norbornene (I) with either the Tebbe reagent (IV) or the titanacycle (V), whose synthesis has been described previously.

Homo-Coupling Reactions of Norbornene Derivatives Catalyzed by Ni-Complexes

The homo-coupling reaction of norbornene (NB) and dicyclopentadiene (DCP) was investigated by using NiX2(R 3P)2-NaBH4 catalyst. This Ni-catalyzed reaction of NB gave homocoupling products, exo-2-(2'-norbornenyl)norbornane (1), bi-2, 2-norbornylidene (2) and exo-2-(4'-methylenecyclohex-1'-en-3'-yl) norbornane (3). Their product distributions depended on the ligand and the halogen bound to Ni-complex as well as the reaction temperature. When the NiCl2(Ph3P)2-NaBH4 system was employed as catalyst, 1 and 2 were formed in preference to 3. It was found that 2 was derived from Ni-catalyzed isomerization of 1, but not the direct coupling of NB. The reaction of NB catalyzed by NiBr2(Bu3P)2, instead of NiCl2(Ph3P)2, afforded the coupling product 3 in good yield. On the other hand, NiX2(R3P)2-NaBH4 catalyzed coupling of endo- and exo-DCP's gave somewhat different results from those of NB.

Organopalladium approaches to prostaglandins. 4. Synthesis of the first interphenylene PGH 2 analogs via benzylpalladation

The reaction of norbornene, norbornadiene and 7-oxanorbornene with methyl 3-(chloromethyl)phenoxyacetate, (S)-1-octyn-3-ol and 8% Pd(PPh 3) 4 affords in one step satisfactory yields of the corresponding, first interphenylene PGH 2 analogs.

Distribution of Alkylboranes in the Reaction of Norbornene and Cyclopentene with Borane–THF

Abstract Systematic studies of the partial alkylation of diborane with norbornene and cyclopentene were carried out in THF and the equilibrium distribution of the borane derivatives was determined. Di-exo-norbornylborane was obtained in 71% yield with no mono-exo-norbornylborane as a by-product, under the conditions: initial ratio of norbornene to borane 2 : 1, temperature 0 °C and reaction time 1 h. Mono-exo-norbornylborane was obtained in 72–75% yield under the conditions: initial ratio of norbornene to borane 1 : 1, temperature 25 °C, and reaction time 48 h. In the dialkylborane [R2BH]2, norbornene and cyclopentene exhibit very different behavior during the course of equilibration reaction.

Photoaddition of Iodoform with Norbornene

AbstractThe reaction of norbornene with iodoform in the inert solvent under irradiation resulted in Kharasch type addition to give endo‐3‐iodo‐exo‐2‐diiodomethyl‐bicyclo[2.2.1]heptane, and a carbene addition to give tricyclic compound, anti‐3‐iodo‐exo‐tricyclo[3.2.1.02,4]octane. The structural assignments of these adducts are based on elemental analyses, ir, nmr, and mass spectral studies.

ChemInform Abstract: THE CHLORINATION OF NORBORNENE BY METAL CHLORIDES AND THE PRODUCT ISOMERIZATION

AbstractDie Chlorierung von Norbornen (I) mit VCl4 in Acetonitril liefert die Produkte (II)‐(VIII) (4: 11.: 7 : 6 :4 : 64 24; Gesamtausbeute 67%) und als Nebenprodukt (IX).

Ring‐Opening polymerization of cycloolefins with catalysts derived from ruthenium and iridium

AbstractAn investigation was carried out on the polymerization of norbornene, cyclopentene and cyclooctene by the following iridium and ruthenium compounds: chlorobis(cyclooctene)iridium (1), carbonylchlorobis(cyclooctene)iridium (2), trifluoroacetatobis(cyclooctene)iridium (3), chloroiridic(IV) acid (4), dichloro(2,7‐dimethylocta‐2,6‐diene‐1,8‐diyl)‐ruthenium (5a), and bis(trifluoroacetato)‐(2,7‐dimethylocta‐2,6‐diene‐1,8‐diyl)ruthenium (5b). All the above catalysts were found to be very active for the polymerization of norbornene via ring‐opening. Iridium catalysts were practically inactive for the polymerization of cyclopentene and cyclooctene, but gave copolymers of norbornene with cyclopentene and cyclooctene via ring‐opening. The ruthenium catalysts displayed no activity for the polymerization of cyclopentene and cyclooctene, but it was found that after treatment with H2 they became active for the polymerization of cyclopentene. The results obtained from the reaction of norbornene and aliphatic olefins suggest that the above catalysts act by metathesis. The particular features of these catalysts were examined.

The Reaction of Norbornene with Lead Tetraacetate and Thallium Trinitrate. Preliminary communication

AbstractThe reaction of norbornene with lead tetraacetate is found to be much more complex than previously reported. In acetic acid and in benzene, the syn‐7‐norbornenyl, 3‐nortricyclyl, and syn and anti‐7‐acetoxy‐exo‐2‐norbornyl acetates were characterized. In methanol, the isolated products represented most of those expected from the competition of methanol and acetate in the neutralization of the intermediate carbocations. The reaction of norbornene with thallium trinitrate in the above solvents yielded very complex mixtures besides the above mentioned products which were formed in about 50% yield.

Bromohydrin formation in dimethyl sulfoxide. V. Reaction of norbornene

Bromohydrin formation in dimethyl sulfoxide. V. Reaction of norbornene

Bromination of Norbornene: the Question of Bromonium Ions vs. 6,1-Hydride Shift

The reaction of norbornene (1) with bromine has been re-investigated and found to give in addition to bromonortricyclene (2) and 2-exo-bromonorbornane (20) a complex mixture of dibromides of which five (15–19) have been isolated and identified. These dibromides have been found to be kinetically controlled products of ionic addition. Apparently dibromide 15 is also formed to some extent in carbon tetrachloride by a radical mechanism. The product composition from the bromine addition has been compared with that of the analogous chlorination and bromofluorination reactions. Degradation of the 2-exo,3-endo-dibromonorbornane from bromination of 5,6-14C-norbornene has shown that this dibromide is formed by two ionic routes: (a) from a bromonium ion 14 (or its equivalent), and (b) from the cation 12 formed by 6,1-hydride shift. Improvements have been made in the first and final steps of the standard norbornene degradation method.

Some free-radical addition reactions of norbornene and related compounds

In the additions of methanethiol, 2-methylpropane-2-thiol, thioacetic S-acid, benzenethiol, and S-deuteriobenzenethiol to norbornene, products of exo–cis-addition are formed. exo-cis-Addition similarly occurs when benzenethiol adds to 2-methylnorborn-2-ene; the phenylthio-radical attacks the more sterically available 3-position, which affords the more highly substituted intermediate radical. In the addition of benzenethiol to both 2-methylene-norbornane and camphene, chain transfer of the intermediate radicals occurs from the exo-direction. When methylene bromide, methyl bromoacetate, and probably ethyl bromoacetate are added to norbornene, products of both trans- and exo–cis-addition are formed, with the latter predominant. These results are best rationalised on the basis of exclusive exo radical attack, since this minimises both steric and torsional strain effects. In the chain-transfer step stereoelectronic interactions between the attacking molecule and the group introduced in the initial radical attack control the exo : endo ratio for direction of chain transfer leading to product formation. In additions of methylene bromide and methyl bromoacetate these interactions are so great that some chain transfer from the endo-side of the radical centre occurs in spite of the increase of torsional strain experienced in the transition state.