Chiral squaramides catalyzed diastereo- and enantioselective Michael addition of α-substituted isocyanoacetates to N-aryl maleimides
作者:Mei-Xin Zhao、Fei-Hu Ji、Deng-Ke Wei、Min Shi
DOI:10.1016/j.tet.2013.09.084
日期:2013.12
An efficient diastereo- and enantioselective Michael addition of α-substituted isocyanoacetates to N-aryl maleimidescatalyzed by quinine or cyclohexane-1,2-diamine derived squaramide catalysts has been disclosed, affording the corresponding adducts in good yields (up to 99%), high diastereoselectivities (up to >20:1 dr) and good to excellent enantioselectivities (up to 94% ee) under mild conditions
Cinchona alkaloid thiourea mediated asymmetric Mannich reaction of isocyanoacetates with isatin-derived ketimines and subsequent cyclization: enantioselective synthesis of spirooxindole imidazolines
作者:Mei-Xin Zhao、Lei Jing、Hao Zhou、Min Shi
DOI:10.1039/c5ra17075c
日期:——
The organocatalyzed asymmetric Mannich reaction of isocyanoacetates with isatin ketimines and subsequent cyclization were developed, leading to spirooxindole imidazolines in high yields and excellent stereoselectivities.
Metal‐free Decarboxylative Annulation of 2‐Aryl‐2‐isocyano‐acetates with Aryldiazonium Salts: General Access to 1,3‐Diaryl‐1,2,4‐triazoles
作者:Yu‐Ting Tian、Fa‐Guang Zhang、Jing Nie、Chi Wai Cheung、Jun‐An Ma
DOI:10.1002/adsc.202001016
日期:2021.1.5
Isocyanoacetates are versatile substrates for the synthesis of heterocyclic compounds, but the concomitant decarboxylation remains rare. Herein we report a decarboxylative annulation reaction of 2‐aryl‐2‐isocyanoacetates with aryldiazonium salts. This metal‐free, base‐promoted protocol allows for the access to a broad collection of 1,3‐diaryl‐1,2,4‐triazoles, including chiral triazole‐based binaphthalene
organocatalytic asymmetric tandem conjugate addition–protonation of α-substituted isocyanoacetates to 2-chloroacrylonitrile catalyzed by dihydroquinine-derived thiourea has been investigated, affording the corresponding adducts with two non-adjacent tertiary–quaternary stereocenters in excellent yields (up to 99%) along with good to excellent diastereo- and enantioselectivities (up to 20 : 1 dr, up to 95%
Dual-reagent organophosphine catalyzed asymmetric Mannich reactions of isocyanoacetates with N -Boc-aldimines
作者:Xiong Ji、Wei-Guo Cao、Gang Zhao
DOI:10.1016/j.tet.2017.08.031
日期:2017.10
A combination of an amino-acid derived chiral phosphine catalyst and methyl acrylate has been employed to catalyze the direct Mannich reaction of α-aryl isocyanoacetate and N-Boc-aldimines efficiently. The loading of the catalyst could be as low as 0.5 mol% without compromise on the yield and enantioselectivity and the corresponding chiral adducts were obtained in excellent yields (up to 98%) and good