The Domino Chromone Annulation and a Transient Halogenation-Mediated C–H Alkenylation toward 3-Vinyl Chromones
作者:Leiqing Fu、Zhongrong Xu、Jie-Ping Wan、Yunyun Liu
DOI:10.1021/acs.orglett.0c03548
日期:2020.12.18
Reported in this paper is a step economical method toward the general synthesis of 3-vinyl chromones via the reactions between readily available o-hydroxyphenyl enaminones and various alkenes. The domino C–H alkenylation and chromone annulation of the enaminones are involved, which enables the synthesis of 3-vinyl chromone products using both terminal and internal alkenes via a key process of transient C–H
Efficient Synthesis of Chromones with Alkenyl Functionalities by the Heck Reaction
作者:Tamás Patonay、Attila Vasas、Attila Kiss-Szikszai、Artur M. S. Silva、José A. S. Cavaleiro
DOI:10.1071/ch10295
日期:——
the Heck reaction in the field of chromones has been demonstrated. Bromochromones with the halogen atom in their rings A and B were reacted with various terminal alkenes to give hitherto unknown alkenyl‐substituted chromones. Reactivity of the substrates was found to markedly depend on the position of the bromineatom. Under phosphine‐free conditions using a phase‐transfer catalyst additive (tetrabutylammonium
Heterodiene cycloadditions: Preparation and transformations of some substituted pyrano[4,3-b][1]benzopyrans
作者:Simon J. Coutts、Timothy W. Wallace
DOI:10.1016/s0040-4020(01)85668-4
日期:1994.1
Heterodienecycloadditions of 4-oxo-4H-1-benzopyrans with formyl, acetyl, or carboxyl substituents at C-3 to 1-alkoxy- or 1,1-dialkoxyalkenes produce 3-alkoxy- or 3,3-dialkoxy-4,4a- dihydropyrano[4,3-b][1]benzopyran-10-ones which are capable of a variety of selective transformations, including acid-induced epimerisation and/or retro-cycloaddition, reduction, hydrolysis and alcoholysis, in some cases
4-氧代-4 H -1-苯并吡喃在C-3处具有甲酰基,乙酰基或羧基取代基的异二烯环加成反应会生成3-烷氧基-或3,3-二烷氧基-4, 4a-二氢吡喃并[4,3- b ] [1]苯并吡喃-10-酮,在某些情况下,能够在多种条件下进行多种选择性转化,包括酸诱导的差向异构和/或逆环加成,还原,水解和醇解非常温和的条件。
Palladium(II)-Catalyzed Direct Intermolecular Alkenylation of Chromones
作者:Donghee Kim、Sungwoo Hong
DOI:10.1021/ol2018278
日期:2011.8.19
A new efficient method for the direct alkenylation of chromones via a palladium(II)-catalyzed C-H functionalization reaction was developed. The use of pivalic acid with Cu(OAc)(3)/Ag2CO3 provided superior reactivity in the cross-coupling of chromones with alkene partners. This approach represents a significant advance over the existing two-step method and afforded various 3-vinylchromone derivatives, which are privileged structures in many biologically active compounds and versatile synthetic building blocks.
Heterocyclic Systems; 15<sup>1</sup>. Formation and Hydrolysis of the [4 + 2]-Cycloadduct of 4-Oxo-4<i>H</i>-[1]benzopyran-3-carboxaldehyde with Ethyl Vinyl Ether
作者:Chandra Kanta Ghosh、Nimai Tewari、Atanu Bhattacharyya