Brønsted acid-catalyzed conjugate addition of quinone methides by azlactones and indoles

2018 ◽  
Author(s):  
Jiyao Yan
Keyword(s):  
Conjugate Addition ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Quinone Methides ◽  
Brönsted Acid ◽  
Acid Catalyzed

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 ◽  
...  
Keyword(s):  
Efficient Method ◽  
Research Area ◽  
Environmentally Benign ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Efficient Synthesis ◽  
Quinone Methides ◽  
Efficient Approach ◽  
Brönsted Acid ◽  
Acid Catalyzed

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.

Brønsted Acid Catalyzed Domino 1,6-Addition/Intramolecular Cyclization­ Reactions: Diastereoselective Synthesis of Dihydro­coumarin Frameworks

Synthesis ◽  
2017 ◽  
Vol 50 (06) ◽  
pp. 1307-1314 ◽  
Author(s):  
Guang-Jian Mei ◽  
Zheng Cao ◽  
Gui-Xiang Zhou ◽  
Chun Ma ◽  
Kang Jiang
Keyword(s):  
Hydrogen Bonding ◽  
Crucial Role ◽  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Diastereoselective Synthesis ◽  
Quinone Methides ◽  
Hydrogen Bonding Interactions ◽  
Brönsted Acid ◽  
Acid Catalyzed

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.

Synthesis of Pyrrolo[1,2-a]indoles via (3+2)-Annulations of (Aza)-para-Quinone Methides with Indoles

Synthesis ◽  
2020 ◽  
Vol 52 (23) ◽  
pp. 3640-3649 ◽  
Author(s):  
Xiang-Zhi Zhang ◽  
Bao Qiong Li ◽  
Zong-Wang Qiu ◽  
Gui-Hua Wen ◽  
Ai-Jun Ma ◽  
...  
Keyword(s):  
Conjugate Addition ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Quinone Methides ◽  
Propargylic Alcohols ◽  
Brönsted Acid

An efficient and straightforward Brønsted acid mediated (3+2)-annulation of (aza)-para-quinone methides, generated in situ from propargylic alcohols and indoles, has been developed involving 1,8-conjugate addition/5-endo annulation cascade. This protocol affords a mild and effective method for the construction of synthetically important and structurally interesting functionalized pyrrolo[1,2-a]indoles.

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