| 5 | Author
| Erich Hitzel | Requires cookie* | | Title
| Abbau von Induktionsperioden und Steigerung der Aktivität homogener Hydrierungskatalysatoren mit Iridium als Zentralatom Reduction of Induction Periods and Increase of Activity of Homogenous Iridium Hydrogenation Catalysts  | | | Abstract
| With complexes of iridium as catalysts, induction periods are typical for homogeneous hydrogenation of olefins in bulk. The induction period decreases, as a rule with increasing activity, at higher temperatures and may be suppressed with dibenzoylperoxide, azo-bisisobutyrodinitrile, tetrachloro-l,4-benzoquinone or by preactivation. Triethylamin and SnCl2 • 2H2O are unsuitable additives. The operation "preactivation" leads additionally to great substrate/catalyst-turnover numbers. | | |
Reference
| Z. Naturforsch. 33b, 997—1000 (1978); eingegangen am 19. Juni 1978 | | |
Published
| 1978 | | |
Keywords
| Catalysis, Hydrogenation, Induction Periods, Activity | | |
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| default:Reihe_B/33/ZNB-1978-33b-0997.pdf | | | Identifier
| ZNB-1978-33b-0997 | | | Volume
| 33 | |
7 | Author
| Henri Brunner, Bernd Haßler | Requires cookie* | | Title
| Enantioselective Catalysis, 122 [1] Synthesis of New Optically Active 3.5-DinitrosalicyloxazoIines  | | | Abstract
| New optically active 3,5-dinitrosalicyloxazo-lines, derived from 3,5-dinitrosalicylonitrile and the chiral aminodiols (lS,2S)-(+)-2-am ino-l-phe-nyl-l,3-propanediol, (2S)-(-)-2-amino-l,l,4,4-te-traphenyl-l,4-butanediol and (2S)-(-)-2-amino-l,l-diphenyl-l,3-butanediol, were prepared and used as in situ catalysts for enantioselective cyclo-propanation reactions. | | |
Reference
| (Z. Naturforsch. 53b, 126—128 [1998]; eingegangen am 27. O ktober 1997 3.) | | |
Published
| 1998 | | |
Keywords
| 5-Dinitrosalicyloxazolines, Enantioselectivity, Catalysis, Cyclopropanations | | |
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| default:Reihe_B/53/ZNB-1998-53b-0126_n.pdf | | | Identifier
| ZNB-1998-53b-0126_n | | | Volume
| 53 | |
10 | Author
| Walter Strohmeier, Manfred Michel, Luise Weigelt | Requires cookie* | | Title
| mit homogenen Ir-und Ru-Katalysatoren Selective Bulk-Hydrogenation of a,ß Unsaturated Ketones to Ketones with Homogeneous Ir and Ru Catalysts  | | | Abstract
| a,ß Unsaturated ketones are selectively hydrogenated to ketones in homogeneous bulk-catalysis under mild conditions by iridium-and ruthenium complexes. The range of mean turnover is from 6 to 196 depending on substrate, catalyst and reaction conditions. Selectivity ketone/alcohol depends on the degree of conversion and exceeds 100 on con-version of 90%. Einleitende Bemerkungen | | |
Reference
| Z. Naturforsch. 35b, 648—650 (1980); eingegangen am 7. Dezember 1979 | | |
Published
| 1980 | | |
Keywords
| Catalysis, Homogeneous, Selective, Hydrogenation, Unsaturated Ketones | | |
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| default:Reihe_B/35/ZNB-1980-35b-0648.pdf | | | Identifier
| ZNB-1980-35b-0648 | | | Volume
| 35 | |
11 | Author
| WolfgangK. Läuia, Susanne Schoger2, Martin Niegerb | Requires cookie* | | Title
| Synthesis and Crystal Structure of Perhydro-l,4-benzoxazino[2,3-n]phenoxazine  | | | Abstract
| The oxidation of fra«s-2-aminocyclohexanol with nitrobenzene in the presence of catalytic amounts of iron inter alia yields perhydro-l,4-benzoxazino[2,3-n]phenoxazine (1). This com pound has been characterized analytically, spectroscopically and by X-ray diffraction. It is postulated that the oxidation of the 2-aminoalcohol leads to the intermediate formation of a 1,2-dione. The direct synthesis of 1 from trans-2-aminocyclohexanol and 1,2-cyclohexandione supports this hypothesis. | | |
Reference
| Z. Naturforsch. 52b, 801—804 (1997); eingegangen am 14. Oktober 1996 | | |
Published
| 1997 | | |
Keywords
| Nitrobenzene, Reduction, Aniline, 2-Aminoalcohols, Catalysis | | |
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| default:Reihe_B/52/ZNB-1997-52b-0801.pdf | | | Identifier
| ZNB-1997-52b-0801 | | | Volume
| 52 | |
12 | Author
| M. Fernanda, N. N. Carvalho3, ArmandoJ L Pombeiro3, Gabriele Wagner3, Bj0m Pedersenb, Rudolf Herrmann | Requires cookie* | | Title
| Cascade Reaction of Camphor-Derived Diynes with Transition Metal Compounds  | | | Abstract
| Platinum(II) catalyzes the isomerization o f camphor sulfonamide diynes in a cascade reaction involving annulation o f a five-membered ring to the camphor skeleton, ring-enlargement by C-C bond cleavage, reduction o f sulfur(VI) to sulfur(IV), and oxidation o f a hydroxy group to a ketone. The reactions o f the diynes with other transition metal compounds were also studied. Copper, gold and rhenium give final products similar to those obtained with simple Br0nsted acids or halogens, mainly by annulation o f a five-membered ring to the camphor moiety, accompanied by reduction o f a sulfonamide to a sulfinamide group, but lacking the ring-enlargement step. Palladium(II) occupies an intermediate position as both types o f products are obtained. The reaction mechanism and intermediates are discussed. | | |
Reference
| Z. Naturforsch. 54b, 725—733 (1999); received March 18 1999 | | |
Published
| 1999 | | |
Keywords
| Camphor Diyne, Ring Enlargement, Transition Metals, Catalysis, Alkyne | | |
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| default:Reihe_B/54/ZNB-1999-54b-0725.pdf | | | Identifier
| ZNB-1999-54b-0725 | | | Volume
| 54 | |
13 | Author
| Christian Egger, Ulrich Schubert | Requires cookie* | | Title
| Metallkomplexe in Anorganischen Matrices, 5 [1] Katalytische Silanoxidation an einem heterogenisierten Rhodium-Komplex M etal Complexes in Inorganic Matrices, 5 [1] Catalytic Silane Oxidation at a Heterogenized Rhodium Complex  | | | Abstract
| A heterogenized rhodium complex, prepared by sol-gel processing of Rh(CO)Cl[PPh2C H 2C H 2Si(OEt)3]2 and Si(OEt)4, is shown to catalyze the conversion of the si lanes H4_"SiPh" (n = 1 -3) or (H M e2Si)20 to (poly)siloxanes by air or water. Using T H F as a solvent, the silanoles Ph3SiOH or Ph2Si(OH)2 are obtained instead. The reaction of phenyl-acetic acid or acetic acid with HSiPh3 to give silyl esters is catalyzed by the same com pound. | | |
Reference
| Z. Naturforsch. 46b, 783—788 (1991); eingegangen am 14. Januar 1991 | | |
Published
| 1991 | | |
Keywords
| Heterogenized Rhodium Complex, Catalysis, Silanes, Silanoles, Siloxanes, Silyl Esters | | |
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| default:Reihe_B/46/ZNB-1991-46b-0783.pdf | | | Identifier
| ZNB-1991-46b-0783 | | | Volume
| 46 | |
14 | Author
| Stephan Pitter, EckhardD. Injus, Beate Jung, H. Elm, Ar Görls | Requires cookie* | | Title
| Phosphinoalkylnitrile: Synthese und Koordinationsverhalten an Palladiumzentren Phosphinoalkylnitnles: Synthesis and Coordination Behaviour at Palladium C entres  | | | Abstract
| Phosphinoalkylnitriles R2P-(CH2)"-CN {R = isopropyl ('pr), phenyl (ph), cyclohexyl (' hex), n -3, 6, 10} have been prepared starting from the corresponding secondary phosphines in an easy three step synthesis. All new compounds were characterized by their 'H -, i3C and 31P NMR data. Some of these new P, N ligands were used to prepare complexes [{R2P-(CH2)"-CN}2PdCl2] which were also identified by their NMR data. In addition the crystal structures of three derivatives, [{'pr2P-(CH2)3-CN }2PdCl2] 7a, [{ph2P-(CH2)3-CN }2PdCl2) 7b and [{ph2P-(CH 2)6-CN}2PdCl2] 8b were determined by X-ray analysis. The coordination mode of the phosphinoalkylnitriles in these complexes was found to be P-bonded resulting in a trans configuration. Palladium catalysts with 5a as ligand show high activies in the co-oligomerization of butadiene and carbon dioxide. The ^-lactone 11a is formed under very mild conditions. | | |
Reference
| Z. Naturforsch. 51b, 934—946 (1996); eingegangen am 11. Juli 1995 | | |
Published
| 1996 | | |
Keywords
| Phosphinoalkylnitriles, Phosphine Complexes of Palladium, Crystal Structure, Catalysis, -Lactones | | |
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| default:Reihe_B/51/ZNB-1996-51b-0934.pdf | | | Identifier
| ZNB-1996-51b-0934 | | | Volume
| 51 | |
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