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
Enantioselectivealdolreactions of various isatins with ketones using newly designed amino amide organocatalysts were found to provide chiral 3-substituted 3-hydroxy-2-oxindoles in good to excellent yields and with excellent stereoselectivities (up to 99 %, up to 98 % ee, syn/anti = 99:1); one catalyst, 3i, proved particularly successful. One of the resulting oxindoles, 3-hydroxy-3-(2-oxocyclohexyl)-2-indolinone
EnantioselectiveAldol Reaction Between Isatins and Cyclohexanone Catalyzed by Amino Acid Sulphonamides
作者:Jun Wang、Qi Liu、Qing Hao、Yanhua Sun、Yiming Luo、Hua Yang
DOI:10.1002/chir.22433
日期:2015.4
Sulphonamides derived from primary α‐aminoacid were successfully applied to catalyze the aldolreaction between isatin and cyclohexanone under neat conditions. More interestingly, molecular sieves, as privileged additives, were found to play a vital role in achieving high enantioselectivity. Consequently, high yields (up to 99%) along with good enantioselectivities (up to 92% ee) and diastereoselectivities
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.