Synthesis of functionalized tetrahydrofuran derivatives from 2,5-dimethylfuran through cascade reactions
作者:J. Li、E. Muller、M. Pera-Titus、F. Jérôme、K. De Oliveira Vigier
DOI:10.1039/c9gc01060b
日期:——
its further aldol condensation with aldehydes, and hydrogenation–cyclization of the condensation intermediate to generate alkylated tetrahydrofuran. Active and selective catalysts could be identified for the aldol condensation and hydrogenation–cyclization reactions.
complexes 2, which undergo loss of the metal fragment at room temperature to form 1,2-diketones 3, 1,2-hydroxy ketones 4, or dimers 5 through a dimerization or decarbonylation-dimerization process of acyl radicals. Decomposition of 2 in the presence of electron-deficient alkenes 11 and 18 furnishes the two-, three-, and four-component coupling products 12, 13, 19, 20, and 21.
Oxidative Ring Contraction of Cyclobutenes: General Approach to Cyclopropylketones including Mechanistic Insights
作者:Andreas N. Baumann、Franziska Schüppel、Michael Eisold、Andrea Kreppel、Regina de Vivie-Riedle、Dorian Didier
DOI:10.1021/acs.joc.8b00297
日期:2018.5.4
cyclopropylketones (CPKs) under atmospheric conditions is reported. Comprehensive mechanistic studies are proposed to support this novel, yet unusual, rearrangement. Insights into the mechanism ultimately led to simplification and generalization of the ring contraction of cyclobutenes using mCPBA as an oxidant. This unique and functional group tolerant transformation proceeds under mild conditions at room temperature
1-Alkenyl cyclopropylketones, when activated by cation-stabilizing substituents at the ring carbon or at the terminal carbon of the enone moiety, undergo polyphosphoric acid-catalyzed ring enlargement producing cyclopentanone or cyclohexenone derivatives. Similar acid-catalyzed ring opening of 1-alkenyl 2-phenoxycyclopropyl ketones offers a convenient and effective synthesis of 4-oxo-5-alkenals and