Oxokohlenstoffe und verwandte Verbindungen; 21. Mitteilung.<sup>1</sup>Diels-Alder Reaktion von 3-Halogeno-3-cyclobuten-1,2-dionen mit 1,1′-Bi-1-cycloalkenylen: Synthese dicycloalkano-anellierter Dihydrobenzocyclobutendione und Benzocyclobutendione
作者:Arthur H. Schmidt、Christian Künz、Marianne Malmbak、Jörg Zylla
DOI:10.1055/s-1994-25490
日期:——
Oxocarbons and Related Compounds; Part 21.1 Diels-Alder Reactions of 3-Halogeno-3-cyclobutene-1,2-diones with 1,1′-Bi-1-cycloalkenyls. Synthesis of Dicycloalkano-annulated Dihydrobenzocyclobutenediones and Benzocyclobutenediones On controlled heating to 100°C, 3-chloro-3-cyclobutene-1,2-diones (5a) reacted with 1,1′-bi-1-cyclohexenyl (6) and 1, 1′-bi-1-cyclopentenyl (13) to give the dicycloalkano-annulated dihydrobenzocyclobutenediones 7 and 16, respectively. Treatment of carbon tetrachloride solutions of 7 and 16 with bromine at reflux temperature afforded the corresponding benzocyclobutenediones 9 and 17. Surprisingly, the reaction of 5a with 1,1′-bi-1-cycloheptenyl (14) and 1,1′-bi-1-cyclooctenyl (15) gave directly the benzocyclobutenediones 20 and 21. The hitherto unknown 3-bromo-3-cyclobutene-1,2-dione (5c) was prepared by treatment of 3-hydroxy-3-cyclobutene-1,2-dione (5b) with oxalic dibromide in 76% yield. Its reaction with the dienes 6, 13, 14 has been investigated.
Multimetallic Ni- and Pd-Catalyzed Cross-Electrophile Coupling To Form Highly Substituted 1,3-Dienes
作者:Astrid M. Olivares、Daniel J. Weix
DOI:10.1021/jacs.7b13601
日期:2018.2.21
synthesis of highly substituted 1,3-dienes from the coupling of vinyl bromides with vinyl triflates is reported for the first time. The coupling is catalyzed by a combination of (5,5'-bis(trifluoromethyl)-2,2'-bipyridine)NiBr2 and (1,3-bis(diphenylphosphino)propane)PdCl2 in the presence of a zinc reductant. This method affords tetra- and penta-substituted 1,3-dienes that would otherwise be difficult
作者:Sylvie L. Tardif、Andrzej Z. Rys、Charles B. Abrams、Imad A. Abu-Yousef、Pierre B.F. Lesté-Lasserre、Erwin K.V. Schultz、David N. Harpp
DOI:10.1016/s0040-4020(97)00555-3
日期:1997.8
The chemistry of the generation and trapping of diatomicsulfur (S2) and sulfur monoxide (SO) are reviewed with special emphasis on recent work, including initial efforts to detect and trap diatomic selenium (Se2).
Diels-alder reactions with 2,2-bis(trifluoromethyl)-ethylene-1,1-dicarbonitrile as dienophile
作者:Reinhard Brückner、Rolf Huisgen
DOI:10.1016/s0040-4039(00)76886-9
日期:1994.5
In the cycloadditions of the title compound BTF to methylated and phenylated butadienes, NMR spectra of adducts allow to draw the demarcation line between [4+2] and [2+2] cycloadditions. 1-Substituted butadienes accept BTF in the direction less hindered by the bulky CF3 groups. In rate comparison with TCNE, BTF shows electronic acceleration and steric deceleration.
Herein, we successfully achieve this goal by employing a recyclable solid acid/ionicliquidcatalyst system. The dehydration of alkyl- and cycloalkyl-derived diols in an Amberlyst-15/[Emim]Cl system afforded the corresponding 1,3-dienes in good yields, while a Nafion/[Emim]Cl system was demonstrated to be a better catalyst system for the dehydration of aryl-substituted substrates. Our protocol features