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Schmidt EM Gleiter R Rominger F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(8):1814-1822
The synthesis of 1-alkyl and 1-aryl-1-azacyclotetradeca-3,5,10,12-tetraynes was achieved in a stepwise approach. The key intermediate was 1,13-dibromotrideca-2,4,9,11-tetrayne (18). Reaction with methyl- (19 a), ethyl- (19 b), isopropyl- (19 c), n-butyl- (19 d), and tert-butylamine (19 e) as well as aniline (19 f) and p-methoxyaniline (19 g) gave the corresponding 14-membered tetraynes 20 a-20 g. The ring inversion process of 20 b was studied by variable temperature (1)H NMR spectroscopy. From these measurements a value of 10.6 kcal mol(-1) was calculated for DeltaG(not equal). X-ray investigations on single crystals of 20 b, 20 c, and 20 f revealed the axial position for the substituent at each nitrogen atom. For 20 b we encountered the chair conformation, for 20 c both chair and boat conformations, and for 20 f the boat conformation in the solid state. The reaction of 20 c with concentrated HCl in ethanol yielded 2,10-dichloro-6-isopropyl-6-azatricyclo[9.3.0.0(4,8)]tetradeca-1(11),2,4(8),9-tetraene (25 c). Compound 25 c was oxidized by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to 27 c. The structure of the latter was confirmed by X-ray investigations. The reaction of 20 c in aqueous HCl lead to the formation of 10-chloro-2-isopropyl-1,3,4,6,7,8-hexahydro-2H-benzo[g]isoquinolin-9-one (37 c). The structure of 37 c was verified by X-ray studies on single crystals. 相似文献
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Dennis Dittrich Heiko Tewes Christoph Wölper Dieter Bläser Stephan Schulz Joachim Roll 《Transition Metal Chemistry》2017,42(3):237-241
Reaction of [Zn4(µ4-O)(O2CCH3)6] with one equivalent of 4-tertiary-butylpyridine leads to a nearly quantitative formation of the heptanuclear cluster [Zn7O2(O2CCH3)10(tbupy)2] (1). Here, we present the crystal structure of 1 and first results of the examination of its catalytic activity in transesterification reactions and polymerization of lactide compared to the activity of [Zn4(µ4-O)(O2CCH3)6] in the presence of 4-tertiary-butylpyridine. 相似文献
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The anomalous reactivity of the bicyclo [2.2.1] heptene double bond is interpreted in terms of hyperconjugative effects, leading to an exceptionally low endo out-of-plane deformation potential. 相似文献
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Rolf Gleiter 《Angewandte Chemie (International ed. in English)》1992,31(1):27-44
The synthesis of Cycloalkadiynes with medium-sized rings may be accomplished by a number of ring-closing and elimination reactions. Information concerning the conformation of the rings as well as the extent of transannular interaction between the triple bonds is obtained by analysis of X-ray crystallographic data and by photoelectron spectroscopy. The diacetylene complexes of Ag1 and Cu1 show hardly any structural change compared to the uncomplexed compounds while the bis(hexacarbonyldicobalt) complexes differ significantly in their structural parameters. Reaction of Cycloalkadiynes with dicarbonyl(η5-cyclopentadienyl)cobalt yields inter- and intramolecular cyclobutadiene complexes. The superphane of cyclobutadiene formed by the intermolecular reaction can be transformed into a number of highly strained cage compounds in few steps. In addition, the variety of such cage compounds can be increased if the reaction of a cyclic diacetylene is carried out with dimethylacetylenedicarboxylate in the presence of aluminum chloride. The intermediate bridged Dewar benzenes eventually lead to propellaprismanes. 相似文献
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[reaction: see text] Pauson-Khand reactions (PKR) of RSCtbd1;CR' (6-10) yielded in all cases as the main product the regioisomer with the alkyl-S group disposed alpha to the CO group (16a-22a). Correlation of these results with X-ray data and charge distribution calculations of the corresponding dicobalthexacarbonyl complexes proves that a recently postulated "trans effect" in these complexes is not suitable for predicting the regiochemical outcome of the PKR unambiguously. 相似文献
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