Modifizierte Wichterle-Reaktion. Ein Weg zur Darstellung von 2-Cyclohexenonen und 1,4-Diketonen. Synthese von 4-Estren-3,17-dion und Dihydrojasmon
作者:Makoto Kobayashi、Takeshi Matsumoto
DOI:10.1246/bcsj.52.2978
日期:1979.10
Wahrend die Behandlung von 2-(3-Chlor-2-butenyl)-2-methylcyclohexanon mit konz. H2SO4 2,5-Dimethylbicyclo[3.3.1]non-2-en-9-on als Hauptprodukt ergab, wurde beim Erhitzen in HCO2H in Anwesenheit von HClO44a-Methyl-Δ1(8a)-2-octalon in 70 bis 98%-iger Ausbeute erhalten. Unter diesen Bedingungen reagierten andere α(Chlorbutenyl)ketone analog und lieferten die entsprechende Annelierungsprodukte in hohen
Wahrend die Behandlung von 2-(3-Chlor-2-butenyl)-2-methylcyclohexanon mit konz。H2SO4 2,5-二甲基双环[3.3.1]non-2-en-9-on als Hauptprodukt ergab, wurde beim Erhitzen in HCO2H in Anwesenheit von HClO44a-Methyl-Δ1(8a)-2-octalon in 70 bis 98%艾格 Ausbeute erhalten。Unter diesen Bedingungen reagierten andere α(Chlorbutenyl)ketone analog und lieferten die entsprechende Annelierungsprodukte in hohen bis massigen Ausbeuten。Aus
A Practical Protocol for Asymmetric Synthesis of Wieland-Miescher and Hajos-Parrish Ketones Catalyzed by a Simple Chiral Primary Amine
primary amine catalyzed efficient and practical protocol for the large-scale synthesis of Wieland–Miescher and Hajos–Parrishketones as well as their analogues. This article describes a simple chiral primary amine catalyzed efficient and practical protocol for the large-scale synthesis of Wieland–Miescher and Hajos–Parrishketones as well as their analogues.
A Highly Active Polymer-Supported Catalyst for Asymmetric Robinson Annulations in Continuous Flow
作者:Santiago Cañellas、Carles Ayats、Andrea H. Henseler、Miquel A. Pericàs
DOI:10.1021/acscatal.6b03286
日期:2017.2.3
preparation through Robinson annulation of enantiopure buildingblocks with both academic and industrial relevance, such as the Wieland–Miescher and Hajos–Parrish ketones, has suffered from important drawbacks, such as the need for high catalyst loading or extremely long reaction times. Here we report a heterogenized organocatalyst based on Luo’s diamine for fast and broad-scope enantioselective Robinson
efficient and practical protocol for the synthesis of both Wieland–Miescher ketone and Hajos–Parrishketone as well as their analogues. The reaction can be conducted in gram scale with 1% mol catalyst loading producing high enantioselectivity (up to 96% ee) and excellent yields (up to 98%). This procedure represents one of the most efficient methods for the synthesis of these versatile chiral building blocks
Efficient Solvent-Free Robinson Annulation Protocols for the Highly Enantioselective Synthesis of the Wieland-Miescher Ketone and Analogues
作者:Ben Bradshaw、Gorka Etxebarría-Jardi、Josep Bonjoch、Santiago F. Viózquez、Gabriela Guillena、Carmen Nájera
DOI:10.1002/adsc.200900321
日期:2009.10
A highly efficient (93% overall yield) and enantioselective (94% ee) synthesis of the Wieland–Miescher ketone (10-g scale) through a solvent-free Robinsonannulation procedure is reported. The process involves only 1 mol% triethylamine as the base in the initial Michael process and the organocatalyst N-tosyl-(Sa)-binam-L-prolinamide (2 mol%) and benzoic acid (0.5 mol%) for the intramolecular aldol