| | 2 | Author
| D. Bryce-Smith, A. Gilbert, N. Al-Jalal, R. R. Deshpande, J. Grzonka, M. A. Hems, P. Yianni | Requires cookie* | | | Title
| Acid and Polarity Effects in Benzene Photoreactions with Alkenes and Alkynes  | | | | Abstract
| The effects of polar solvents and proton donors on various photoreactions of the benzene ring with electron-acceptor alkenes and alkynes are described and discussed in relation to the various electronic excitation mechanisms involved. Proton donors prove valuable as mechanistic probes for polar intermediates in such processes, and can in some systems both initiate and divert reaction pathways. In 1970 we observed that the course of the photo-chemical cycloadditions of certain ethylenic and acetylenic compounds to benzene, earlier reported by us [1, 2], was profoundly altered in the presence of proton donors, leading to a type of photochemical Friedel-Crafts reaction [3]. Since then, we have described, mostly in preliminary form, numerous further examples of acid catalysis in the photo-reactions of benzene, viz. with amines [4], ethers [5], a ketone [6], a carboxylic acid [6], and hexa-fluorobenzene [7]. Our objective in this present paper is to bring together the previous preliminary reports on acid catalysis in the photoreactions of ethylenic and acetylenic compounds with benzene in conjunction with unpublished recent findings, and to provide a mechanistic rationale together with relevant experimental details. But before we proceed to consider the acid-cata-lysed processes, it is desirable to summarise the main types of reaction that have been shown to occur in the absence of acids. Ethylenes and/or acetylenes photoadd to benzene in the following four main ways: (a) ortho cycloaddition; (b) meto-cycloaddi-tion; (c) £>ara-cycloaddition; and (d) para-ene addi-tion [8, 9]. The mode of addition varies with the addend, and in some cases more than one pathway may be followed. In the case of (a), the adducts (1) of ethylenes may be obtained as such when the ethylenic addend is not a strong thermal dienophile, e.g. acrylonitrile [10], 2,3-dihydropyran [11]. When it is a strong dienophile, as in the case of maleic * Reprint requests to Prof. D. Bryce-Smith. 0340-5087/83/0900-1101/$ 01.00/0 anhydride and certain maleimides, a second mole-cule may add thermally to give the remarkably | | | |
Reference
| Z. Naturforsch. 38b, 1101—1112 (1983); received May 2 1983 | | | |
Published
| 1983 | | | |
Keywords
| Photoreactions, Benzene, Alkenes, Alkynes, Acid Effects | | | |
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| default:Reihe_B/38/ZNB-1983-38b-1101.pdf | | | | Identifier
| ZNB-1983-38b-1101 | | | | Volume
| 38 | |
| 3 | 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 | |
| 4 | Author
| J. Breidung, H. Bürger, M. Senzlobei^, W. Thiel | Requires cookie* | | | Title
| High Resolution FTIR Spectrum of Chlorofluoroethyne | | | | Abstract
| , FCCC1, below 1000 cm -1 . Analysis of the v v v v v s , 2v 4 , v A + v 5 and 2i/ 5 Bands, and ab initio Calculations High resolution infrared spectra of FCCC1 have been measured and analyzed by polynomial methods. In the region below 350 cm -1 , the analysis is straightforward and yields parameters for the V4 = 1 and = 1 states. Between 350 and 800 cm -1 there are strong anharmonic interactions in the 2v 5 /u 4 + u^lu^llu^ tetrad which have been unravelled with the use of a model that employs ab initio interaction constants. Observed and theoretically predicted wavenumbers are in excellent agreement for all bands studied. | | | |
Reference
| Z. Naturforsch. 54a, 236—244 (1999); received December 2 1998 | | | |
Published
| 1999 | | | |
Keywords
| Infrared Spectrum, High Resolution, Alkyne, Fermi Resonance, ab initio Calculations | | | |
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| default:Reihe_A/54/ZNA-1999-54a-0236.pdf | | | | Identifier
| ZNA-1999-54a-0236 | | | | Volume
| 54 | |
| 5 | Author
| Rainer Diercks, Heindirk Tom Dieck | Requires cookie* | | | Title
| Diazadiene als Steuerliganden in der Homogenen Katalyse, VIII [1] Katalytische Trimerisierung substituierter Acetylencarbonsäureester und Isolierung eines Acetylendicarbonsäureester-Diazadien-Nickel(O)-Addukts Diazadienes as Controlling Ligands in Homogeneous Catalysis, VIII [1] Catalytic Trimerization of Substituted Acetylene Carbonic Acid Esters and Isolation of an Acetylene Dicarbonic Acid Ester Diazadiene Nickel(O) Adduct | | | | Abstract
| Nickel(O) complexes of diazadienes (dad = RN = CR — C R '=N R) catalyse the trimerization of esters of 2-butynoic acid, phenylpropynoic acid and butynedioic acid to give hexasubstituted benzenes with the unsymmetrical esters 2 as the main products. A primary adduct 7 of acetylene dicarboxylic acid dimethyl ester of the type (dad)Ni(alkyne) could be isolated and characterized by 'H NMR, IR and UV spectroscopy. According to their characteristic CT absorption. 7 and its analogues are shown to persist during catalysis as an active species. | | | |
Reference
| Z. Naturforsch. 39b, 180 (1984); eingegangen am 24. August 1983 | | | |
Published
| 1984 | | | |
Keywords
| Catalytic Trimerization, Diazadiene Nickel Complexes, Alkynes, Hexasubstituted Benzenes, Alkyne Complexes | | | |
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| default:Reihe_B/39/ZNB-1984-39b-0180.pdf | | | | Identifier
| ZNB-1984-39b-0180 | | | | Volume
| 39 | |
| 6 | Author
| KlausR. Pörschke, Richard Mynott, Klaus Angermund, ++, Carl Krüger | Requires cookie* | | | Title
| Neue Bis(phosphan)-nickel(0)-alkin-Komplexe New Bis(phosphane)-nickel(0)-alkyne Complexes | | | | Abstract
| (Me 3 P)2Ni(C 2 H4) (5) and (dmpe) 2 Ni2(C 2 H4)3 (6) react with various alkynes including ethyne (acetylene) and 1-alkynes to form the crystalline compounds (Me 3 P) 2 Ni(C 2 RR'), (dmpe)Ni(C 2 RR'), and (dmpe)2Ni 2 (C 2 R2) 2 (R.R' = H, Me, Ph). Structural assignments were made on the basis of : H, I3 C, and 31 P NMR data. The crystal and molecular structure of (dmpe)Ni(C 2 Ph 2) (17) has been determined by X-ray crystallography. | | | |
Reference
| Z. Naturforsch. 40b, 199—209 (1985); eingegangen am 15. Oktober 1984 | | | |
Published
| 1985 | | | |
Keywords
| Alkynes, Nickel(O), Phosphanes, NMR Spectra, X-Ray | | | |
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| default:Reihe_B/40/ZNB-1985-40b-0199.pdf | | | | Identifier
| ZNB-1985-40b-0199 | | | | Volume
| 40 | |
| 7 | Author
| Herwig Schottenberger, Michael Buchmeiser, Johann Polin, K. Arl-, Eberhard Schwarzhans | Requires cookie* | | | Title
| Ferrocen-Derivate der Quadrat-und Propiolsäure. Synthesen und Reaktionen Ferrocene Derivatives of Squaric Acid and Propiolic Acid. Syntheses and Reactions | | | | Abstract
| Concepts for linking ferrocene derivatives with conjugated squarate and propiolate based spacer systems have been investigated. Coupling o f 3,4-dichlorocyclobut-3-ene-l,2-dione (squaric acid dichloride) with cuproferrocene • dim ethylsulfide resulted in 3-chloro-4-ferrocenylcyclobut-3-ene-l,2-dione (ferrocenylsemisquaric acid chloride) and 3,4-diferro-cenylcyclobut-3-ene-l,2-dione. Ferrocenylsemisquaric acid chloride was further treated with ethynylferrocene and 4-ethynyl-4-(ferrocenylethynyl)tolan, respectively, to form the corre sponding mixed squaric diketones, which required Zn/Pd mediated coupling conditions for sufficient conversion. The symmetrically substituted derivative o f ferrocenylacetylene was pre pared by the same method. Cupration and subsequent coupling o f dilithioferrocene with one equivalent o f iodopro-piolic acid methyl ester yielded l'-iodo-l-ferrocenylpropiolic acid methyl ester, and with two equivalents l,16-bis(m ethoxycarbonylethynyl)biferrocene. N ucleophilic addition o f secondary amines to ferrocenylpropiolic acid ethyl ester gave aminoacrylates as intermediates, which rap idly converted to ketoesters during workup. Only in the case o f morpholine the corresponding adduct (ferrocenylmorpholino acrylate) could be isolated. l,3-Diferrocenylprop-2-ene-J-one has been obtained in a Benary reaction o f lithioferrocene with 3-diethylam inoethyl acrylate in quantitative yield. In order to provide alternative syntheses o f already known com pounds the substitution be havior o f different metallated ferrocene intermediates has also been evaluated by reaction with other acid halides (oxalyl chloride, thiophosgene, ethyl chloroformate). All new com pounds, 3-chloro-4-ferrocenylcyclobut-3-ene-l,2-dione (1); | | | |
Reference
| Z. Naturforsch. 48b, 1524—1532 (1993); eingegangen am 8. Juli 1993 | | | |
Published
| 1993 | | | |
Keywords
| Ferrocenes, Alkynes, Squaric Acid Derivatives, Propiolic and Acrylic Esters | | | |
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| default:Reihe_B/48/ZNB-1993-48b-1524.pdf | | | | Identifier
| ZNB-1993-48b-1524 | | | | Volume
| 48 | |
| 8 | Author
| Roberto Millini, Horst Kisch, Carl Krüger | Requires cookie* | | | Title
| Iron Carbonyl Assisted Synthesis of l,2-Diazepin-3-ones from Cyclic Diazenes and Alkynes [1] | | | | Abstract
| , 2a, c are prepared by an iron carbonyl mediated reaction sequence from alkynes and cyclic 1,2-diazenes. The latter are first converted into hexacarbonyl diiron complexes which react with two molecules of an alkyne to afford tricyclic carbonyl iron compounds I —III. Oxidative degradation with bromine leads to these novel heterocycles whose structure is confirmed by an X-ray analysis of lb. | | | |
Reference
| Z. Naturforsch. 40b, 187—192 (1985); received October 15 1984 | | | |
Published
| 1985 | | | |
Keywords
| Diazepinones, Diazenes, Alkynes, Carbonyl-Iron Assistance Bicyclic l, 2-diazepin-3-ones la—c | | | |
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| default:Reihe_B/40/ZNB-1985-40b-0187.pdf | | | | Identifier
| ZNB-1985-40b-0187 | | | | Volume
| 40 | |
|
