A Novel Skeleton Transformation of 2a-Substituted 2a,8b-Dihydro-3H-benzo[b]cyclobuta[d]pyran-3-ones to 2-(2-Oxoethyl)-2H-1-benzopyrans Promoted by a Combination of ZnI2, Organic Base and H2O
A Multicomponent Coupling Reaction Induced by Insertion of Arynes into the CO Bond of Formamide
作者:Eito Yoshioka、Shigeru Kohtani、Hideto Miyabe
DOI:10.1002/anie.201102088
日期:2011.7.11
And aryne makes three: The three‐component coupling of arynes, DMF, and active methylenes has provided an efficient method for the synthesis of 2H‐chromene and coumarin derivatives (see scheme). The sequential multistep reactions are driven by the release of strain energy in the arynes and intermediates, and this finding was supported by thermodynamics.
A Molecular Iodine-Mediated Synthesis of Cyclopenta[<i>c</i>]furo[3,2-<i>b</i>]furan-5,6-diones: Assembly of an Angular Dioxatriquinane Core
作者:Issa Yavari、Ramin Mohsenzadeh、Parisa Ravaghi
DOI:10.1021/acs.joc.1c02572
日期:2022.3.4
A molecular iodine-mediated synthesis of angular oxatriqinane core from 3-acetyl-2H-chromen-2-ones, β-bromo-β-nitrostyrenes, and pyridine in the presence of Et3N in MeCN containing a trace amount of water was developed. The reaction proceeds via intermolecular Michael reaction of 2-oxo-2-(2-oxo-2H-chromen-3-yl)-1-(pyridin-1-ium-1-yl)ethan-1-ide with bromonitrostyrene followed by intramolecular Michael
在含有微量水的 MeCN 中,在Et 3 N 存在下,分子碘介导的 3-乙酰基-2 H -chromen -2-ones、β-溴代-β-硝基苯乙烯和吡啶合成角氧杂三嗪核心是发达。该反应通过 2-oxo-2-(2-oxo-2 H -chromen-3-yl)-1-(pyridin-1-ium-1-yl)ethan-1-ide 与溴硝基苯乙烯的分子间迈克尔反应进行通过分子内迈克尔反应和消除步骤。典型产品的立体化学证据来自单晶 X 射线分析。该策略的重要特征是它形成了三个具有良好选择性的立体中心。
[4+2] cycloaddition of intermediates generated from arynes and DMF
作者:Eito Yoshioka、Hirofumi Tamenaga、Hideto Miyabe
DOI:10.1016/j.tetlet.2013.12.119
日期:2014.2
The trappingreaction of the transient intermediateortho-quinone methides, generated by the insertion of arynes into a carbon–oxygen double bond of DMF, with dienophiles was investigated. The [4+2] cycloaddition products were obtained when the diesters of acetylenedicarboxylic acid were employed as dienophiles.
A Novel Skeleton Transformation of 2a-Substituted 2a,8b-Dihydro-3<i>H</i>-benzo[<i>b</i>]cyclobuta[<i>d</i>]pyran-3-ones to 2-(2-Oxoethyl)-2<i>H</i>-1-benzopyrans Promoted by a Combination of ZnI<sub>2</sub>, Organic Base and H<sub>2</sub>O
The novel skeleton transformation reaction of 2a-substituted 2a,8b-dihydrobenzo[b]cyclobuta[d]pyran-3-one derivatives into 2-(2-substituted 2-oxoethyl)-2H-1-benzopyran derivatives has been accomplished using Znl2 in the presence of an organic base and water in excellent yields.