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Jürg Krebs Dominik Guggisberg Urs Stmpfli Markus Neuenschwander 《Helvetica chimica acta》1986,69(4):835-848
Synthesis of Triafulvene Precursors for Retro-Diels-Alder Reactions Triafulvene precursors exo? 15 and endo? 15 have been prepared by addition of dibromocarbene to benzobarrelene 12 followed by a lithium-halogen exchange, methylation, and elimination of HBr ( 12→13→14→15 ), (Scheme 2). Gas-phase pyrolysis of exo/endo-mixtures of 15 above 400° gave minor amounts of naphthalene ( 16 ), traces of a hydrocarbon C4H4 identified by MS (presumably triafulvene 1 ) and predominantly (36%) the isomerization product 17 (Scheme 3). In a second synthetic approach the well-known cycloheptatriene-norcaradiene equilibrium of type 26?27 has been utilised to prepare various endo-trans-3-(X-methyl) tricyclo[3.2.2.02,4]nona-6,8-dienes 31 (Scheme 5). However, numerous elimination experiments 31→9 failed so far. The structure of two rearrangement products 33 and 34 (Scheme 6) has been elucidated. 相似文献
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Angela Metz Alexander Hoffmann Kristina Hock Sonja Herres‐Pawlis 《Chemie in Unserer Zeit》2016,50(5):316-325
Bioplastics represent an important possibility to reduce environmental pollution by non‐degradable plastics and open up new resources for plastics production. To promote wide application of bioplastics, new catalysts are urgently needed. This article summarises recent developments of robust lactide polymerisation catalysts as well as the embedding of the produced PLA into the life cycle of bioplastics. 相似文献
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Prof. Dr. Armin Reller 《无机化学与普通化学杂志》2012,638(10):1552-1552
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The preparation of a series of non-cyclic, electrically neutral ligands, able to selectively complex alkaline earth metal cations, is described. Some of the compounds show high Ca2+ selectivity in membrane electrodes. 相似文献
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Reaction of Trimethylsilylethers of Unsaturated Alcohols with Schwartz Reagent – Stabilisation of Cyclic Zirconiumorganic Compounds by the Moiety Cp2ZrH2 Besides the normal product of hydrozirconation the reaction of allyltrimethylsilylethers CH2? CHC(R1R2)OSi(CH3)3 ( I : R1 = R2 = H, VIII : R1 = R2 = CH3, X : R1 = H, R2 = CH3) with Cp2Zr(H)Cl yields, as a result of a hydrogenation of the Si? O bond, trimethylsilane and a series of compounds with a Zr? O bond. Depending on the substitution of the α-C atom either dimeric chelates ( III ) or binuclear complexes of the type Cp2Zr(Cl)CH2CH2C(R1R2)OZr(Cl)Cp2 ( IX : R1 = R2 = CH3; XII : R1 = H, R2 = CH3) are formed. Starting with X and excess Cp2Zr(H)Cl the binuclear compound XIII is obtained which may be considered as an adduct of Cp2ZrH2 to the unsaturated chelate Compound XVII with a structure analogous to XIII is synthesized by the reaction of IX with Cp2ZrH2. The 1H-NMR spectrum is in accordance with the existence of cis-trans-isomers of this complex. 相似文献
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《Nachrichten aus der Chemie》2017,65(10):1007-1007
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