Efficient Synthesis of Chromenes from Vinyl o-Quinone Methides via a Brønsted Acid Catalyzed Electrocyclization Process

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.

2018 ◽  
Vol 20 (1) ◽  
pp. 261-265 ◽  
Author(s):  
Waqar Ahmed ◽  
Sheng Zhang ◽  
Xiaoqiang Yu ◽  
Yoshinori Yamamoto ◽  
Ming Bao

A convenient and efficient method for quinoline synthesis was developed using simple and readily available starting materials under green conditions.


2014 ◽  
Vol 1 (10) ◽  
pp. 1197-1200 ◽  
Author(s):  
Qingjiang Li ◽  
Xiao-Shui Peng ◽  
Henry N. C. Wong

A simple and efficient approach for the synthesis of disubstituted carbazoles has been developed from o-haloanilines and terminal alkynes using a two-step strategy, namely, Sonogashira coupling and intramolecular cyclization.


Synthesis ◽  
2017 ◽  
Vol 50 (06) ◽  
pp. 1307-1314 ◽  
Author(s):  
Guang-Jian Mei ◽  
Zheng Cao ◽  
Gui-Xiang Zhou ◽  
Chun Ma ◽  
Kang Jiang

An efficient domino 1,6-addition/intramolecular cyclization reaction between para-quinone methides (p-QMs) and azlactones under Brønsted acid catalysis was established. A series of highly functionalized dihydrocoumarins were constructed in good to excellent yields (up to 96%) with excellent diastereoselectivities (all >20:1 d.r.). In this process, the Brønsted acid plays a crucial role not only in activating the two substrates, but also in controlling the diastereoselectivity of the reaction via hydrogen-bonding interactions. In addition, this protocol demonstrates the great practicability of utilizing p-QMs in domino reactions.


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