Showing papers on "Norbornadiene published in 1992"
TL;DR: In this paper, the insertion of alkenes in Pd-acetyl bonds of (dppp)Pd(C(O)CH3)Cl and (PP)pd(c(O),CH3),L)]+ SO3CF3− (pP = dppe, dppp, DPPP, dPPP; L CH3CN, PPh3) have been studied as a function of the ligand, the anion and the alkene.
142 citations
TL;DR: In this article, a trichlorosilane was used to hydrosilylate norbornene in the presence of palladium catalyst (0.01-0.1 mol %) coordinated with ( R )-MOP ligand, which was oxidized with hydrogen peroxide to give (1 S,2 S,4 R ) -exo -2-norbornanol in 96% ee.
95 citations
TL;DR: In this paper, the anti rotamers of Mo(CHCMe2Ph)(NAr)OCMe(CF3)2 complexes were determined by NMR methods.
Abstract: : Anti rotamers of Mo(CHCMe2Ph)(NAr)(OR)2 complexes (Ar = 2,6-C6H3-i- Pr2; OR = OCMe2(CF3), OCMe(CF3)2, and OC(CF3)2(CF2CF2CF3)) can be generated at -80 deg in toluene by photolysis at 366 nm and the rate of conversion of anti to syn rotamers determined by NMR methods. At equilibrium the anti rotamers can be observed by high field proton NMR at 25 deg after many transients and values for Keq(syn/anti) thereby determined. Keq can be determined at O deg when OR = OCMe3 and k anti/syn estimated. The rate of conversion of the anti to the syn rotamer in toluene is found to vary by at least five orders of magnitude as the alkoxide is changed from t-butoxide to OC(CF3)2(CF2CF2CF3). The results in THF are analogous, although the rates of rotamer interconversion are much slower for any given alkoxide. Addition of 2,3-bis(trifluoromethyl)norbornadiene to mixtures containing both anti and syn Mo(CHCMe2Ph)(NAr)OCMe(CF3)2)2 showed that in both toluene and THF the anti rotamer was orders of magnitude more reactive than the syn rotamer.
84 citations
TL;DR: The ligand 2-(2'-pyridyl)-4,5-dimethylphosphinine, NIPHOS, reacts with the compounds [Ir 2 Cl 2 (COD) 2 ] and [Rh 2 Cl2 (NBD) 2 ], respectively, to give the binuclear cations as discussed by the authors, which were isolated as their [SbF 6 ] - salts.
Abstract: The ligand 2-(2'-pyridyl)-4,5-dimethylphosphinine, NIPHOS, reacts with the compounds [Ir 2 Cl 2 (COD) 2 ] (COD =1,5-cyclooctadiene) and [Rh 2 Cl 2 (NBD) 2 ] (NBD=norbornadiene) to give the binuclear cations [Ir 2 (COD) 2 - (NIPHOS) 2 ] 2+ and [Rh 2 (NBD) 2 (NIPHOS) 2 ] 2+ , respectively, which were isolated as their [SbF 6 ] - salts.
50 citations
TL;DR: In the presence of a trapping agent, α,β-unsaturated selenoaldehydes and selenoketones, generated in situ by selenation of corresponding carbonyl compounds with bis[dimethylaluminum) selenide, underwent regioselective self-condensation to yield cyclic diselenide derivatives as discussed by the authors.
37 citations
TL;DR: In this paper, an X-ray analysis was performed on the facially coordinated tridentate histidinate ligand with the coordinating imidazole nitrogen is now in transposition to the chlorine atom.
36 citations
TL;DR: On heating, bis(cyclopentadienyl)tetracarbonyldimolybdenum-alkyne complexes undergo a cycloaddition with norbornadiene or norbornene to afford the corresponding-3 substituted cyclopentenone derivatives, which could heardly be obtained in the cobalt-complexed alkyne-mediated Pauson-Khand reaction as discussed by the authors.
Abstract: On heating, bis(cyclopentadienyl)tetracarbonyldimolybdenum-alkyne complexes undergo a [2 + 2 + 1] cycloaddition with norbornadiene or norbornene to afford the corresponding-3 substituted cyclopentenone derivatives, which could heardly be obtained in the cobalt-complexed alkyne-mediated Pauson-Khand reaction.
30 citations
TL;DR: In this paper, the azine diphosphine Z,Z-PPh2CH2C(But)N-N-But)CCH2PPh21 was treated with H2O2 and with monoclinic sulfur to give the diphophosphine disulfide 2b.
Abstract: Treatment of the azine MeC(But)NNC(But)Me with 2 equivalents of LiBun, followed by 2 equivalents of PPh2Cl, gives the azine diphosphine Z,Z-PPh2CH2C(But)N–N(But)CCH2PPh21. This new diphosphine was treated with H2O2 to give the corresponding diphosphine dioxide 2a and with monoclinic sulfur to give the diphosphine disulfide 2b. Treatment of [M(CO)3(η6-cht)](cht = cyclohepta-2,4,6-triene) with 1 gave the metal tricarbonyl fac-[[graphic omitted]Ph2}](M = Mo, 3a; W, 3b; or Cr, 3c) in which the azine diphosphine is bonded in the E,Z configuration. Complexes 3a and 3b were also made by treating the corresponding metal hexacarbonyls with the azine diphosphine 1. Treatment of [M(CO)4(nbd)](M = Mo, W, or Cr; nbd = norbornadiene) with 1 gave the tetracarbonyl complexes [[graphic omitted]Ph2}]4 with the E,Z-azine diphosphine acting as a bidentate ligand. On heating, these tetracarbonyl complexes 4 were converted into the tricarbonyl complexes 3. Treatment of either 3a or 4a with 1 mol equivalent of bromine gave the neutral molybdenum(II) complex [[graphic omitted]Ph2}]5, whereas the tungsten complexes 3b and 4b with bromine gave the cation [[graphic omitted]Ph2}]+ isolated as its BPh4– salt 6. Proton, 13C-{1H} and 31P-{1H} NMR and infrared data are given. Crystals of 1 are monoclinic, space group P21/n, with a= 1667.2(2), b= 572.85(6), c= 1811.0(2) pm, β= 111.595(8)° and Z= 2; final R factor 0.0519 for 2049 observed reflections. Crystals of 3a are monoclinic, space group P21/n, with a= 985.7(1), b= 1870.2(2), c= 2220.8(2) pm, β= 93.71(1)° and Z= 4, final R factor 0.0354 for 5219 observed reflections.
29 citations
TL;DR: In this article, a variety of homopolymers of norbornadiene and copolymers with norbornene have been synthesized using a range of olefin metathesis catalysts.
29 citations
28 citations
TL;DR: The photochemical valence isomerization of pendant norbornadiene (NBD) to the quadricyclane (QC) moiety in poly(4-(chloromethyl)-styrene] with their corresponding potassium salts was described in this paper.
Abstract: Polymers having a pendant 3[(p-substituted phenyl)carbamoyl]-2,5-norbornadiene-2-carboxylate moiety were prepared by the reaction of poly(4-(chloromethyl)-styrene] with their corresponding potassium salts. The photochemical valence isomerization of pendant norbornadiene (NBD) to the quadricyclane (QC) moiety proceeded smoothly in the film state or polymer solution upon irradiation by sunlight. The rate of isomerization was strongly affected by the nature of the substituent. The resulting QC groups in the polymer film scarcely reverted to the original NBD without any catalyst if it were kept in dark at room temperature for a long time.
TL;DR: In this paper, a photoresponsive polymers bearing norbornadiene (NBD) moieties were synthesized in high yields without any insoluble gel products by the selective cationic polymerization of 2-[[(3-phenyl-2,5-norbornadienyl)-2-carbonyl]oxy] ethyl vinyl ether (PNVE) and also by the copolymerizations with 2-phenoxyethyl vinyl ether, 2-chloroethyl, or isobutyl (IsO(C 2 H 5 )a
Abstract: New photoresponsive polymers bearing norbornadiene (NBD) moieties were synthesized in high yields without any insoluble gel products by the selective cationic polymerization of 2-[[(3-phenyl-2,5-norbornadienyl)-2-carbonyl]oxy] ethyl vinyl ether (PNVE) and also by the copolymerizations with 2-phenoxyethyl vinyl ether, 2-chloroethyl vinyl ether, or isobutyl vinyl ether using BF 3 -O(C 2 H 5 )a as a catalyst in dichloromethane solution.
TL;DR: Diphenylneopentylsilene, Ph 2 Si=CHCH 2 t Bu ( 3 ), is prepared as a reactive intermediate by the reaction of diphenylvinylchlorosilane (1 ) with Li t Bu in nonpolar solvents via the α-lithioadduct Ph 2Si(Cl)CH(Li)CH 2 T Bu ( 2 ) This lithiated species can be trapped by trimethylsilyltriflate and yields silene 3 by 1,2-LiCl-elimination without suitable Si
TL;DR: In this article, a rhodium-phosphine catalyst was used to synthesize formyl-pregene, formyl androstene and corresponding aminomethyl derivatives.
Abstract: New formyl-pregene, formyl-androstene and the corresponding aminomethyl derivatives are synthesised selectively via hydroformylation with a rhodium–phosphine catalyst prepared in situ.
TL;DR: In this article, metal-promoted valence isomerization and cycloreversions occur in the gas phase for adducts of norbornadiene and quadricyclane (Q) with either Fe(I) or Cu(I).
Abstract: Metal-promoted valence isomerizations and cycloreversions occur in the gas phase for adducts of norbornadiene (NBD) and quadricyclane (Q) with either Fe(I) or Cu(I). The collisionally activated decomposition (CAD) spectra of the adducts of NBD and Q with each metal indicate that the complexes possess identical structures, although the structures that are formed with Fe(I) are different from those with Cu(I).
Patent•
19 Nov 1992TL;DR: In this article, a method of enantioselectively hydrogenating an olefin, a ketone, or an imine, which comprises carrying out the enanti-lective hydrogenation using as a catalyst the alkali metal sulfonate-substituted binaphthylphosphine transition metal complex represented by formula (I) is also disclosed.
Abstract: An alkali metal sulfonate-substituted binaphthyl-phosphine transition metal complex is disclosed, which is represented by formula (I) [M(X).sub.n (Q)(SO.sub.3 A--BINAP)]Y (I) wherein M represents a transition metal atom; SO 3 A--BINAP represents a tertiary phosphine represented by formula (II) ##STR1## in which A represents an alkali metal atom; X represents a chlorine atom, a bromine atom, or an iodine atom; when n is 1, M represents ruthenium, Q represents benzene or p-cymene, and Y represents a chlorine atom, a bromine atom, or an iodine atom; when n is 0 and M is iridium or rhodium, Q represents 1,5-cyclo-octadiene or norbornadiene, and Y represents ClO 4 , PF 6 or BF 4 ; and when n is 0 and M is palladium, Q represents π-allyl, and Y represents ClO 4 , PF 6 , or BF 4 . A method of enantioselectively hydrogenating an olefin, a ketone, or an imine, which comprises carrying out the enantioselective hydrogenation using as a catalyst the alkali metal sulfonate-substituted binaphthylphosphine transition metal complex represented by formula (I) is also disclosed.
TL;DR: In this article, reactions of selenobenzophenones with dimethyl acetylenedicarboxylate or norbornadiene gave benzoselenapyranes or seven-membered cyclic selenides; these reactions might proceed through unusual type of cycloaddition reaction.
TL;DR: The molecular structure of [Rh(SnCl 3 )(norbornadiene)(dppp) as mentioned in this paper, where dppp = 1,3-bis(diphenylphosphino)propane, has been determined by an X-ray diffraction study.
TL;DR: In this paper, a twisted intramolecular charge transfer (TICT) excited state is used for electron transfer photochemistry starting from a TICT excited state, using N-(α-naphthyl)carbazole (NC) as sensitizer.
Abstract: Electron transfer photochemistry starting from a twisted intramolecular charge transfer (TICT) excited state is shown, using N-(α-naphthyl)carbazole (NC) as sensitizer. The NC TICT state has been used as electron donor and acceptor. This dual reactivity is demonstrated by fluorescence quenching measurements, and the rate constants have been correlated with the help of the Marcus equation. Photochemical reactions have also been performed. Photoisomerization of the quadricyclane into norbornadiene is proof of the radical cationic reactivity of the quadricyclane into norbornadiene is proof of the radical cationic reactivity of the TICT, while photodechlorination of pentachlorobenzene is proof of radical anionic reactivity. A triplet sensitized ring closure of norbornadiene was also shown to occur.
TL;DR: In this paper, the authors report the benzenedithiolatocobalt complex-catalyzed isomerization of quadricyclane (Q) to norbornadiene from the viewpoint of the control of catalytic activities in terms of the reversible half-wave potentials in the reduction step (E r 1/2 (red)) and their ability to form adducts with Q.
TL;DR: Synthesis of New Photoresponsive Polyamides Containing Norbornadiene Residues in the Main Chain this paper, where the residuals in the main chain
Abstract: Synthesis of New Photoresponsive Polyamides Containing Norbornadiene Residues in the Main Chain
TL;DR: In this article, multifunctional polymeric photosensitizers were prepared by partial substitution reaction of poly(p-(chloromethyl)styrene) or insoluble chloromethelated polystyrene bead with potassium 4-nitro-1-naphtaxide or 4nitrophenoxide using a phase transfer catalyst.
Abstract: Multifunctional polymeric photosensitizers were prepared by partial substitution reaction of poly(p-(chloromethyl)styrene) or insoluble chloromethylated polystyrene bead with potassium 4-nitro-1-naphtaxide or 4-nitrophenoxide using a phase transfer catalyst followed by an addition reaction of tertiary amines or phosphines on the remaining chloromethyl groups. The rates of the photochemical valence isomerization of potassium 3-phenyl-2,5-norbornadiene-2-carboxylate (PNC) in the presence of these photosensitizers were significantly higher than those of PNC with low molecular weight photosensitizers in methanol.
TL;DR: In this article, the NMR spectra of 2,5-norbornadiene (Nbd)-quadricyclene valence and trans-cis-stilbene photoisomerization in THF at 366 nm were analyzed.
TL;DR: Deltacyclene (tetracyclo[4,3.0,02,903,7]non-4-ene) was stereoselectively hydroformylated to exo-formyl-deltacyCLane in the presence of rhodium and platinum catalysts.
Abstract: Deltacyclene (tetracyclo[4,3.0,02,903,7]non-4-ene was stereoselectively hydroformylated to exo-formyl-deltacyclane in the presence of rhodium and platinum catalysts. In the case of optically active bisphosphines up to 22 96 e.e-s were achieved.
TL;DR: In this article, the reaction of norbornadiene(tetracarbonyl)-chromium and -tungsten (2) with aryllithium reagents, ArLi (Ar C6H5, o-,m-,p-CH3C6H4, p-CH 3OC6H 4, p -CF3C 6H4), in ether at low temperature, and subsequent alkylation of the acylmetalate intermediates formed with Et3OBF4 in aqueous solution at 0°C
TL;DR: In this paper, new cage lactones were synthesized by photocyclization of tricyclodienolactones 1a, 1b, 2 which were available from the Diels-Alder reactions of 2-pyrones with p-benzoquinones or norbornadiene.
TL;DR: In this paper, the possibility of using Pt II complexes, such as norbornadiene/Pt II complex, as catalysts for step-polymerization without side-reactions, instead of PT IV compounds like H 2 PtCl 6.