γ-Carbonyl Quinones: Radical Strategy for the Synthesis of Evelynin and Its Analogues by C–H Activation of Quinones Using Cyclopropanols
摘要:
Cyclopropanols, on oxidative ring opening with AgNO3-K2S2O8 in DCM-H2O at room temperature and under open flask conditions, produced beta-keto radicals which were successfully added to quinones to furnish gamma-carbonyl quinones. This mild method has been applied to the synthesis of cytotoxic natural products, 4,6-dimethoxy-2,5-quinodihydrochalcone and evelynin.
Unveiling the Reactivity of Propargylic Hydroperoxides under Gold Catalysis
作者:Benito Alcaide、Pedro Almendros、M. Teresa Quirós、Ramón López、María I. Menéndez、Aleksandra Sochacka-Ćwikła
DOI:10.1021/ja3108966
日期:2013.1.16
Controlled gold-catalyzed reactions of primary and secondary propargylic hydroperoxides with a variety of nucleophiles including alcohols, phenols, 2-hydroxynaphthalene-1,4-dione, and indoles allow the direct and efficientsynthesis of β-functionalized ketones. Moreover, the utility of some of the resulting products for the selective preparation of fused polycycles has been demonstrated. In addition
伯和仲炔丙基氢过氧化物与各种亲核试剂(包括醇、酚、2-羟基萘-1,4-二酮和吲哚)的受控金催化反应允许直接有效地合成 β-官能化酮。此外,已经证明了一些所得产物用于选择性制备稠合多环的效用。此外,还进行了密度泛函理论 (DFT) 计算和 (18) O 标记实验,以深入了解炔丙基氢过氧化物与外部亲核试剂在金催化下的受控反应性的各个方面。
Synthesis of Siloxy-α-Lapachone Derivatives by Chemo- and Regioselective Diels-Alder Reactions of 3-Methylene-1,2,4-naphthotriones with Silyl Enol Ethers
2-hydroxy-1,4-naphthoquinone with aliphatic and aromatic aldehydes, take part in chemoselective hetero-Diels-Alder reactions with silyl enolethers to give a series of siloxy-containing naphtho[2,3- B]pyran-5,10-dione (α-lapachone) derivatives in moderate to high yield. These reactions regio-selectively gave α-lapachone derivatives with an acetal structure. This regioselectivity can be rationalized by