Brønsted acid cocatalysis in photocatalytic intramolecular coupling of tertiary amines: efficient synthesis of 2-arylindols

2016 ◽  
Vol 14 (31) ◽  
pp. 7447-7450 ◽  
Author(s):  
Xiaoqian Yuan ◽  
Xinxin Wu ◽  
Shupeng Dong ◽  
Guibing Wu ◽  
Jinxing Ye

We report herein a highly efficient intramolecular coupling reaction of tertiary amines and ketones (α,β-unsaturated ketones) by using a Brønsted acid as a cocatalyst, affording 2-arylindols in good to excellent yields (up to 92%) under visible light irradiation at room temperature.

2020 ◽  
Vol 56 (42) ◽  
pp. 5661-5664
Author(s):  
Yukihiro Arakawa ◽  
Tomohiro Mihara ◽  
Hiroki Fujii ◽  
Keiji Minagawa ◽  
Yasushi Imada

Visible light irradiation to flavins in the presence of thiols and O2 provides Brønsted acidic species that can be used as efficient catalysts for thioacetalizations and for Mannich-type reactions under non-irradiation and mild conditions.


2018 ◽  
Vol 6 (2) ◽  
pp. 2541-2551 ◽  
Author(s):  
Lingli Ni ◽  
Jiayu Xin ◽  
Kun Jiang ◽  
Lu Chen ◽  
Dongxia Yan ◽  
...  

Synthesis ◽  
2018 ◽  
Vol 50 (12) ◽  
pp. 2416-2422 ◽  
Author(s):  
Man-Su Tu ◽  
Guang-Jian Mei ◽  
Feng Shi ◽  
Si-Jia Liu ◽  
Xiao-Li Jiang ◽  
...  

An efficient approach for the synthesis of chromene derivatives from vinyl o-quinone methides was established via a Brønsted acid catalyzed electrocyclization. By using this methodology, a series of structurally diversified chromenes was synthesized in a highly atom-economic and environmentally benign manner with generally good to excellent yields (up to 98% yield). This reaction will not only provide an efficient method for the construction of chromene scaffolds, but also enrich the research area of o-quinone methides.


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