Functionalized Hexahydropyrrolo[2,1-b ]oxazoles from Catalyst-Free Annulation of Δ1 -Pyrrolines with Electron-Deficient Propargylic Alcohols

2020 ◽  
Vol 2020 (27) ◽  
pp. 4181-4192
Author(s):  
Ludmila A. Oparina ◽  
Dmitrii A. Shabalin ◽  
Anastasiya G. Mal'kina ◽  
Nikita A. Kolyvanov ◽  
Lyudmila A. Grishchenko ◽  
...  
2021 ◽  
Vol 19 (7) ◽  
pp. 1508-1513
Author(s):  
Sengodagounder Muthusamy ◽  
Muthukumar Malarvizhi ◽  
Eringathodi Suresh

An unambiguous and precise method for the synthesis of 3,1-benzoxathiin-4-ones/1,3-benzodioxin-4-ones by the reaction of propargylic alcohols and salicylic/thiosalicylic acids under a catalyst-free and open-air atmosphere is described.


2021 ◽  
Author(s):  
Jian-Fei Bai ◽  
Jianbo Tang ◽  
Xiaolong Gao ◽  
Zhi-Jiang Jiang ◽  
Zhanghua Gao

We report a perfluorophenylboronic acid catalyzed cross coupling reaction of tertiary propargylic alcohols and hetero-areneboronic acids for valuable benzo[b]thiophene and cyclopenta[a]indene derivates. This coupling reaction proceeds efficiently with a wide array of substrates scope in up to 89% yield and excellent regioselectivity. A significant advantage of our protocol is the transition metal catalyst free and mild conditions needed. This strategy provides direct and facile access to medicinally important benzo[b]thiophene and cyclopenta[a]indene scaffold containing a quaternary carbon center.


2022 ◽  
Author(s):  
Jian-Fei Bai ◽  
Jianbo Tang ◽  
Xiaolong Gao ◽  
Zhi-Jiang Jiang ◽  
Jia Chen ◽  
...  

We report a perfluorophenylboronic acid catalyzed cross coupling reaction of tertiary propargylic alcohols and hetero-areneboronic acids for valuable benzo[b]thiophene and cyclopenta[a]indene derivates. This coupling reaction proceeds efficiently with a wide array of substrates scope in up to 89% yield and excellent regioselectivity. A significant advantage of our protocol is the transition metal catalyst free and mild conditions needed. This strategy provides direct and facile access to medicinally important benzo[b]thiophene and cyclopenta[a]indene scaffold containing a quaternary carbon center.


2021 ◽  
Author(s):  
Jian-Fei Bai ◽  
Jianbo Tang ◽  
Xiaolong Gao ◽  
Zhi-Jiang Jiang ◽  
Zhanghua Gao

We report a perfluorophenylboronic acid catalyzed cross coupling reaction of tertiary propargylic alcohols and hetero-areneboronic acids for valuable benzo[b]thiophene and cyclopenta[a]indene derivates. This coupling reaction proceeds efficiently with a wide array of substrates scope in up to 89% yield and excellent regioselectivity. A significant advantage of our protocol is the transition metal catalyst free and mild conditions needed. This strategy provides direct and facile access to medicinally important benzo[b]thiophene and cyclopenta[a]indene scaffold containing a quaternary carbon center.


2020 ◽  
Vol 7 (19) ◽  
pp. 2981-2985
Author(s):  
Tao Niu ◽  
Shan Yang ◽  
Xinxin Wu ◽  
Chen Zhu
Keyword(s):  

Described herein is a radical-mediated vinylation of the remote C(sp3)–H bonds of propargylic alcohols.


2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.


2018 ◽  
Author(s):  
Victor Laserna ◽  
Tom Sheppard

A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. Firstly, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxy imines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-aminoalcohols with high syn seletivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway.<br>


2020 ◽  
Vol 17 (9) ◽  
pp. 709-716
Author(s):  
Ebrahim Saeedian Moghadam ◽  
Shahrzad Ghafary ◽  
Mohsen Amini

With regard to the importance of quinazoline as a privileged scaffold, herein we report the synthesis of twenty seven 2,4-disubstitute quinazoline derivatives in a new catalyst free condition. In the current work, poly ethylene glycol (PEG1000) as an inexpensive, very simple commercially available, ecofriendly and low melting point solvent was used. Air bubbling, a green oxidant, for oxidation purpose was also used. This is the first report about using PEG1000 as a solvent simultaneously with air bubbling as oxidant in quinazoline synthesis. All of the compounds 1-27 were synthesized in high yield with very simple work up and purification process without using column chromatography. All the structures were confirmed using 1H NMR, 13C NMR, IR, MS and elemental analysis.


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