Synthesis and photoinduced fluorescence of 3-(2-hetarylethenyl)chromen-2-ones
摘要:
3-(2-Hetarylethenyl)chromen-2-ones were synthesized for the first time, following two different schemes, and their spectral and photochemical properties were studied. The title compounds were found to undergo both reversible and irreversible photoinduced transformations which are accompanied by considerable change of the fluorescence pattern.
Enantioselective Construction of Spirooxindole‐Fused Cyclopenta[
<i>c</i>
]chromen‐4‐ones Bearing Five Contiguous Stereocenters via a Stepwise (3+2) Cycloaddition
作者:Sandip Sambhaji Vagh、Praneeth Karanam、Cheng‐Chieh Liao、Ting‐Han Lin、Yan‐Cheng Liou、Athukuri Edukondalu、Yi‐Ru Chen、Wenwei Lin
DOI:10.1002/adsc.201901655
日期:2020.4.17
The bifunctional quinine‐catalyzed stepwise (3+2) cycloaddition for the enantioselective construction of spirooxindole‐fused cyclopenta[c]chromen‐4‐ones is developed. The reactions of 3‐homoacylcoumarins and alkylidene oxindole electrophiles generate aforementioned spirooxindole‐chromenone adducts bearing five contiguous stereocenters, of which one is the spiro all‐carbon quaternary stereocenter in
Ir(ppy)<sub>3</sub>-Catalyzed, Visible-Light-Mediated Reaction of α-Chloro Cinnamates with Enol Acetates: An Apparent Halogen Paradox
作者:Thomas Föll、Julia Rehbein、Oliver Reiser
DOI:10.1021/acs.orglett.8b02484
日期:2018.9.21
activation of vinyl chloridesderivedfrom α-chloro ethyl cinnamates via oxidative quenching of excited photocatalyst fac-Ir(ppy)3 is described. Upon photoelectron transfer and chloride extrusion, the corresponding vinyl radical can be efficiently trapped by enol acetates, giving rise to synthetically useful 1,4-dicarbonyl compounds in good to excellent yields. This transformation is distinguished by
Diversity‐Oriented Synthesis of Spirocyclohexene Indane‐1,3‐diones and Coumarin‐Fused Cyclopentanes via an Organobase‐Controlled Cascade Reaction
作者:Min Wang、Ping‐Yao Tseng、Woei‐Jye Chi、Sundaram Suresh、Athukuri Edukondalu、Yi‐Ru Chen、Wenwei Lin
DOI:10.1002/adsc.202000597
日期:2020.8.19
An organobase‐controlled, divergent cascade reaction to construct spirocyclohexene indane‐1,3‐diones and coumarin‐fused cyclopentanes is reported. The cascade reaction is triggered by the 1,6‐addition of 3‐homoacylcoumarins to the indanedione‐derived acceptors and further regio/chemoselective reaction that preferentially resulted in spiro systems and fused cyclopentanes in a diversity‐oriented manner
A Novel and Convenient Synthesis of Substituted Coumarins
作者:Alok K. Awasthi、Ram S. Tewari
DOI:10.1055/s-1986-31877
日期:——
Substituted coumarins have been synthesized by the annelation of 2-hydroxyphenyl aldehydes and ketones with carboxylic acids using N,N-dimethyl(dichlorophosphoryloxymethylene)ammonium chloride as phosphorylating agent.
Enantioselective Synthesis of Spiropyrazolone-Fused Cyclopenta[<i>c</i>]chromen-4-ones Bearing Five Contiguous Stereocenters via (3+2) Cycloaddition
作者:Pankaj V. Khairnar、Yin-Hsiang Su、Athukuri Edukondalu、Wenwei Lin
DOI:10.1021/acs.joc.1c01215
日期:2021.9.3
An enantioselectivesynthesis of spiropyrazolone-fused cyclopenta[c]chromen-4-ones is demonstrated via a (3+2) cycloaddition reaction. The reactions of 3-homoacylcoumarins and α,β-unsaturated pyrazolones in the presence of the cinchona-alkaloid derived hydrogen-bonding catalyst provide aforementioned spiropyrazolone-chromenone adducts bearing five contiguous stereocenters, of which one is the spiro
通过 (3+2) 环加成反应证明了螺吡唑酮稠合的 cyclopenta[ c ]chromen-4-ones的对映选择性合成。3-高酰基香豆素与α,β-不饱和吡唑啉酮在金鸡纳生物碱衍生的氢键催化剂存在下反应,得到上述螺吡唑酮-色烯酮加合物,其具有五个连续的立体中心,其中一个是螺环全碳四元立体中心。产率(高达 98%),具有良好到出色的立体选择性(>25:1 dr 和高达 99% ee)。这种一锅法也可以在具有类似功效的克级规模上得到实际证明。