One-pot facile synthesis of polysubstituted pyridines via tandem reaction of the Blaise reaction intermediates and 3-formylchromones
作者:Zhiwei Chen、Zhaoran Dai、Zhangxia Zhu、XiaoFeng Yang
DOI:10.1016/j.tetlet.2017.02.006
日期:2017.3
A novel tandemone-pot method for the synthesis of polysubstituted pyridine derivatives has been developed via Knoevenagel-type reaction and subsequent 6π electrocyclization of the Blaise reaction intermediates and 3-formylchromones. Short reaction time, moderate to good yields and excellent functional group tolerance have been accomplished in this protocol.
addition of the aminoacid derived bifunctional N-acylaminophosphine to an α-substituted allene ester generated a zwitterionic dipole that engaged the vinylogous ester function of 3-cyano-chromones in a [4 + 2] annulation reaction to deliver tetrahydroxanthones embodying three consecutive chiral centers in high yields and with excellent enantioselectivities. The established asymmetric synthesis further paves
Pd-Catalyzed asymmetric decarboxylative cycloaddition of vinylethylene carbonates with 3-cyanochromones
作者:Ijaz Khan、Can Zhao、Yong Jian Zhang
DOI:10.1039/c8cc02456a
日期:——
of vinylethylene carbonates with 3-cyanochromones. By using a palladium complex generated in situ from [Pd2(dba)3]·CHCl3 and phosphoramidite L3 as a catalyst under mild reaction conditions, the process afforded furanobenzodihydropyrans bearing vicinal quaternary stereocenters in high yields with good to high enantio- and diastereoselectivities.
Enantioselective Addition-Alkylation of α,β-Unsaturated Carbonyls via Bisguanidinium Silicate Ion Pair Catalysis
作者:Wenchao Chen、Esther Cai Xia Ang、Siu Min Tan、Zhijie Chua、Jingyun Ren、Ziqi Yang、Bo Teng、Richmond Lee、Haihua Lu、Choon-Hong Tan
DOI:10.1021/jacs.0c00183
日期:2020.11.11
Silicon hydrides, alkynylsilanes, and alkoxylsilanes were activated by fluoride in the presence of bisguanidinium catalyst to form hypervalent silicate ionpairs. These activated silicates undergo 1,4-additions with chromones, coumarins, and α-cyanocinnamic esters generating enolsilicate intermediates, for a consequent stereoselective alkylation reaction. The reduction-alkylation reaction proceeded
Photocatalytic Activity of Triphenylphosphine and Potassium Iodide System in the Decarboxylative Alkylation of 3‐Cyanochromones
作者:Marek Moczulski、Angelika Artelska、Łukasz Albrecht、Anna Albrecht
DOI:10.1002/ejoc.202200630
日期:2022.8.19
In this work, the photocatalytic decarboxylative alkylation of 3-cyanochromone using triphenylphosphine and potassiumiodide as photoredox-mediators is reported. The method is characterized by broad scope and good yields.