Polymer-supported selenium-induced electrophilic cyclization: solid-phase synthesis of poly-substituted dihydrofurans and tetrahydrofurans
摘要:
Poly-substituted dihydrofurans and tetrahydrofurans have been synthesized through polymer-supported selenium-induced intramolecular electrophilic cyclization, followed by selenoxide syn-elimination or novel nucleophilic substitution cleavage of selenium resin with good yields and purities. (C) 2004 Elsevier Ltd. All rights reserved.
Synthesis of Cyclic Enol Ethers from Alkenyl-β-dicarbonyl Compounds
作者:Helena M. C. Ferraz、Myrian K. Sano、Marta R. S. Nunes、Graziela G. Bianco
DOI:10.1021/jo011089+
日期:2002.6.1
the cyclofunctionalization of eleven differently substituted alkenyl-beta-dicarbonyl compounds, employing three electrophilic reagents, namely, iodine, p-methoxyphenyltellurium trichloride, and phenylselenenyl bromide. The reactions occur through the enolic form of the substrates, to afford the corresponding iodo-, telluro-, or selenocyclic enolethers. Substrates bearing trisubstituted double bonds
Efficient synthesis of dihydrofurans and furans by rhodium(II)-catalyzed reactions of cyclic diazodicarbonyl compounds
作者:Yong Rok Lee、Jung Yup Suk
DOI:10.1016/s0040-4020(02)00118-7
日期:2002.3
An efficient synthesis of dihydrofurans and furans is achieved by rhodium-catalyzed reactions of cyclic diazodicarbonyl compounds with allyl halides. This method provides a rapid entry toward naturally occurring furocoumarin and furophenalenone derivatives.
Iodo- and bromo-enolcyclization of 2-(2-propenyl)cyclohexanediones and 2-(2-propenyl)cyclohexenone derivatives using iodine in methanol and pyridinium hydrobromide perbromide in dichloromethane
作者:Malose J. Mphahlele、Thwanthwadi B. Moekwa
DOI:10.1039/b505491e
日期:——
α-Allylcyclohexane-1,3-diones undergo one-pot iodine–methanol promoted iodocyclization and oxidative aromatization to afford variously substituted 2-iodomethyltetrahydrobenzofuran-4-ones (minor) and 2-iodomethyl-4-methoxydihydrobenzofuran derivatives (major). On the other hand, the α-allyl-1,3-cyclohexanediones react with pyridinium hydrobromide perbromide in dichloromethane to afford mixtures of 2-bromomethyltetrahydrobenzofuran-4-ones (major) and 3-bromomethyltetrahydrobenzopyran-5-ones (minor). The prepared products and their derivatives were characterized using a combination of NMR, FT-IR and mass spectroscopic techniques.