Applications of Thermal Activation, Ball-milling and Aqueous Medium in Stereoselective Michael Addition of Nitromethane to Enynones Catalyzed by Chiral Squaramides
作者:Żaneta A. Ignatiuk、Mikołaj J. Janicki、Robert W. Góra、Krzysztof Konieczny、Rafał Kowalczyk
DOI:10.1002/adsc.201801498
日期:2019.3.5
to conjugated en‐ynones was performed through the application of chiral squaramides. Three non‐classical approaches to promote the addition reaction were tested, including activation of the nucleophile by inorganic base in a biphasic aqueous system, thermal activation, and ball‐milling. Hydrogen‐bonding catalysis was effective in all these methods, providing 1,4‐addition products in high yields and
Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
作者:Taoda Shi、Shenghan Teng、Alavala Gopi Krishna Reddy、Xin Guo、Yueteng Zhang、Kohlson T. Moore、Thomas Buckley、Damian J. Mason、Wei Wang、Eli Chapman、Wenhao Hu
DOI:10.1039/c9ob01903k
日期:——
report a bifunctional Ag catalyst promotedintramolecular capture of oxonium ylides with alkynes for the enantioselectivesynthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with
One-pot synthesis of 3-substituted-4<i>H</i>-[1,2,3] triazolo[5,1-<i>c</i>][1,4]oxazin-6(7<i>H</i>)-ones from propargyl alcohols, chloroacetyl chloride, and sodium azide
作者:Xiao-Lan Zhang、Mei-Hong Wei、Jun-Min Chen、Shou-Ri Sheng、Xiao-Ling Liu
DOI:10.1177/1747519820948355
日期:2021.5
An efficient, one-pot synthesis of 3-substituted-4H-[1,2,3]triazolo[5,1-c][1,4]oxazin-6(7H)-ones is developed via sequential esterification, substitution, and 1,3-dipolar cycloaddition processes of...
Pd(<scp>ii</scp>)-catalyzed formal [4+1] cycloaddition reactions of diazoacetates and aryl propargyl alcohols to form 2,5-dihydrofurans
作者:Taoda Shi、Xin Guo、Shenghan Teng、Wenhao Hu
DOI:10.1039/c5cc05000f
日期:——
Pd(ii)-catalyzed auto-tandem formal [4+1] cycloaddition of diazoacetates and aryl propargyl alcohols affords 2,5-dihydrofurans as the dominant product over traditional ones.
Rhodium(II)‐Catalyzed Formal [4+1]‐Cycloaddition of Pyridotriazoles and Propargyl Alcohols: Synthesis of 2,5‐Dihydrofurans
作者:Xinxin Lv、Haijian Yang、Taoda Shi、Dong Xing、Xinfang Xu、Wenhao Hu
DOI:10.1002/adsc.201801497
日期:2019.3.15
A rhodium‐catalyzed formal [4+1]‐cycloaddition of pyridotriazoles and aryl propargylalcohols is reported, providing an effective access to 2‐pyridyl‐substituted 2,5‐dihydrofuran derivatives in moderate to high yields. Mechanistically, the proposed oxonium ylide intermediate in this catalytic alkyne carbocyclization transformation is verified by an interception experiment for the first time.