The synthesis and application of a newly designed C2-symmetric chiral bifunctional triamine family (C2-CBT) is reported. These enantiopure chiral triamine scaffolds can be accessed in multigram amounts from simple amino acids while avoiding chromatographic purification. As a proof of principle, C2-CBT has been studied in the aldol reaction of cyclic ketones with isatins, with the target tertiary alcohols
Organocatalyzed direct asymmetric aldol reaction of isatins in water: low catalyst loading in command
作者:Akshay Kumar、Swapandeep Singh Chimni
DOI:10.1016/j.tet.2013.04.044
日期:2013.6
Simple primary tertiary diamines easily derived from natural primary amino acids have been used to catalyze the aldol reactions in water. The 1 mol % of diamine catalyst is sufficient to catalyze the aldol reaction of cyclohexanone/acetone to isatins provided 3-substituted-3-hydroxy-2-oxindole in good yield and good enantioselectivity. The methodology highlights the importance of low catalyst loading in achieving high enantioselectivity. (C) 2013 Elsevier Ltd. All rights reserved.
2-Azanorbornane-based amine organocatalyst for enantioselective aldol reaction of isatins with ketones
Optically active 2-azanorbornane-based organocatalysts were designed and synthesized, and the catalytic activity of these catalysts in enantioselective aldol reactions of isatins with ketones was investigated. Among these catalysts, 2-azanorbornylmethanol showed the best catalytic activity to afford the corresponding aldol product in excellent chemical yield (up to 95%) and with moderate stereoselectivity (up to 64% ee, up to syn:anti = 36:64). (C) 2016 Elsevier Ltd. All rights reserved.