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
An efficient oxidative conversion of 2-aryl-2H-chromenes to the corresponding flavones by tert-butylhydroperoxide and copper bromide
作者:Dipanwita Banerjee、Utpal Kayal、Gourhari Maiti
DOI:10.1016/j.tetlet.2016.03.006
日期:2016.4
A simple and efficient method has been developed for the facile oxidation of chromenes to the corresponding flavones by tert-butylhydroperoxide (TBHP) in the presence of copper(II) bromide catalyst in toluene at 80 °C in a very short time. The reaction demonstrates excellent reactivity, functional group tolerance, and good to excellent yields without using conventional strong oxidizing agents.
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.