在汞灯下由3-碘黄酮生成乙烯基自由基,并且与五元杂芳烃发生串联环化反应,需要两个连续的CC键形成,以合成苯并[ e ] chromeno [2,3 - g ]吲哚-13(1 H))-一阶导数。串联环化反应在乙腈中进行,没有任何添加剂,例如过渡金属,配体和氧化剂,在温和且环境友好的反应条件下,以高收率产生了各种各样的新型多环x吨酮骨架。
Rh-Catalyzed aldehydic C–H alkynylation and annulation
作者:Maddali L. N. Rao、Boddu S. Ramakrishna
DOI:10.1039/c9ob02670c
日期:——
aldehydic C-Hbond alkynylation and annulation for the in situ synthesis of chromones and aurones are described. It involves the sequential aldehydeC-Hbond alkynylation of salicylaldehyde with in situ generated 1-bromoalkyne from 1,1-dibromoalkene followed by annulation. This protocol shows good functional group tolerance including aryl, alkenyl, alkyl and heteroaryl-1,1-dibromoalkenes. The steric/electronic
The procedure consists of a sequence of some reactions including an arylation/decarboxylation cascade and proceeds well in aqueous media to afford biologically interesting flavones and 3-arylcoumarins. This method exhibited excellent selectivity and functional group tolerance under mild conditions. The reaction also showed perfect efficacy for the preparation of styryl coumarins.
使用K 2 S 2 O 8,实现了色农酮与芳基硼酸的高度区域选择性和无过渡金属的一锅芳基化反应。该程序由一系列反应组成,包括芳基化/脱羧级联,并在水性介质中进行得很好,从而提供了生物学上令人感兴趣的黄酮和3-芳基香豆素。该方法在温和条件下显示出极好的选择性和官能团耐受性。该反应还显示出制备苯乙烯基香豆素的完美功效。
Novel and Efficient Access to Flavones under Mild Conditions: Aqueous HI-Mediated Cascade Cyclization/Oxidative Radical Reaction of 2-Propynolphenols
disclose a metal‐free and efficient method for the direct conversion of 2‐propynolphenols to biologically important flavones using aqueous HI as the promoter. This transformation was proved via 4‐iodo‐2H‐chromenes intermediate, which was simultaneously conversed to corresponding flavones by a Csp2–I bond cleavage and a C–O bond formation under air.
Pd(OAc)<sub>2</sub>/SPPh<sub>3</sub> accelerated activation of gem-dichloroalkenes for the construction of 3-arylchromones
作者:Jianming Liu、Weiwei Song、Yuanyuan Yue、Ren Liu、Hong Yi、Kelei Zhuo、Aiwen Lei
DOI:10.1039/c5cc06334e
日期:——
The Pd-catalyzed regioselective intramolecular nucleophilic substitution of gem-dichloroalkene derivatives with salicylaldehydes leading to the synthesis of 3-arylchromones has been developed.
通过Pd催化的选择性内分子亲核取代,gem-二氯烯衍生物与水杨醛反应,合成了3-芳基香豆素。
Manganese(III) Acetate Mediated Oxidation of Flavanones: A Facile Synthesis of Flavones
作者:Om V. Singh、M. Muthukrishnan、Gopan Raj
DOI:10.1080/00397910500214490
日期:2005.10.1
Abstract Oxidation of flavanones (1a–o) with manganese(III) acetate by heating in acetic acid in presence of perchloric acid afforded exclusively flavones (2a–o) by dehydrogenation in almost quantitative yields.