A series of new modular bifunctional chiral thiourea organocatalysts were synthesized from natural Cinchona alkaloids and amino acids, and their performance in the aza-Henry reaction of nitroalkanes to imines, the Michaeladdition of acetylacetone to nitroolefins and the Michaeladdition of acetone to nitroolefins was investigated. Under the mild conditions, the important building blocks β-nitro amines
motifs in organocatalysis, whereas efficient 1,3‐diamine‐derived organocatalysts are very rare. Herein we report a highly efficient camphor‐1,3‐diamine‐derived squaramideorganocatalyst. Its catalytic activity in Michaeladditions of 1,3‐dicarbonyl nucleophiles to trans‐β‐nitrostyrene derivatives provides excellent enantioselectivities (up to >99% ee).
Ferrocene Analogues of Hydrogen-Bond-Donor Catalysts: An Investigative Study on Asymmetric Michael Addition of 1,3-Dicarbonyl Compounds to Nitroalkenes
作者:Rajiv Trivedi、Kadiyala Rao、M. Kantam
DOI:10.1055/s-0034-1379491
日期:——
moieties. A stepwise sequential route was used to assemble the various components of these ferrocene derivatives. The resulting bifunctional catalysts were used successfully in asymmetric Michael additions of 1,3-dicarbonylcompounds to β-nitrostyrenes. The corresponding products were obtained in high yields and in good to excellent enantioselectivities and diastereoselectivities under mild conditions by
Amphiphilic Hyperbranched Polyethoxysiloxane: A Self-Templating Assembled Platform to Fabricate Functionalized Mesostructured Silicas for Aqueous Enantioselective Reactions
作者:Kun Zhang、Juzeng An、Yanchao Su、Jueyu Zhang、Ziyun Wang、Tanyu Cheng、Guohua Liu
DOI:10.1021/acscatal.6b01315
日期:2016.9.2
precursor. As presented in the study, the chiralruthenium/diamine-functionalized catalyst performs an asymmetric transfer hydrogenation of acyclic α-trifluoromethylimines to chiral α-trifluoromethylamines in water, whereas the chiral squaramide-functionalized catalyst enables efficiently asymmetric Michael addition of acetylacetone to nitroalkenes in brine. Both highly catalytic performances are attributed
Highly efficient and enantioselective Michael addition of acetylacetone to nitroolefins catalyzed by chiral bifunctional organocatalyst bearing multiple hydrogen-bonding donors
作者:Xin Shi、Wei He、Hua Li、Xu Zhang、Shengyong Zhang
DOI:10.1016/j.tetlet.2011.04.043
日期:2011.6
efficient catalyst system for the asymmetric addition of acetylacetone to nitroolefins using a chiral bifunctionalorganocatalyst bearing multiple hydrogen-bonding donors was developed. When using the organocatalyst 2c derived from natural cinchona alkaloid in optimal conditions, up to 98% chemical yield and 98% ee were observed with a variety of aromatic nitroolefins.