Asymmetric construction of quaternary stereocenters by direct organocatalytic amination of 3-substituted oxindoles

ZQ Qian, F Zhou, TP Du, BL Wang, M Ding…

Index: Qian, Zi-Qing; Zhou, Feng; Du, Tai-Ping; Wang, Bo-Lun; Ding, Miao; Zhao, Xiao-Li; Zhou, Jian Chemical Communications, 2009 , # 44 p. 6753 - 6755

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Citation Number: 68

Abstract

Compared with α-arylated cyanoacetates and β-dicarbonyl compounds (pK a ∼ 13), 10a the pK a value of 3-alkyl-substituted oxindoles can be expected to be substantially higher, considering the pK a value of oxindole (18.2). 10b It has not been explored whether Brønsted bases could catalyze the reaction between such less active nucleophiles and azodicarboxylates. Encouraged by the Cinchona alkaloid-catalyzed direct aldol-type reaction of 3-prochiral oxindoles with ...