been established herein by using a trifluoromethylative ring expansion of isatin with trifluorodiazoethane. The strategy provides a platform for the rapid synthesis of a wide range of substituted 3-hydroxy-4-trifluoromethyl-2-quinolinones. This operationally simple and robust Ag-catalyzed protocol successfully transforms isatin ketimines to 3-amino-4-trifluoromethylquinolinones in excellent yields. The
An efficient asymmetricMannichreaction of isatin-based ketimines with α-diazomethylphosphonates has been developed using a chiral binaphthanol-derived silver phosphate as the catalyst. This reaction allowed the construction of a series of chiral oxindoles bearing a quaternary stereocenter and amino group at the C3 position with up to 95% yields and 99% ee. Those products could be further transformed
A Bispidine-Based Chiral Amine Catalyst for Asymmetric Mannich Reaction of Ketones with Isatin Ketimines
作者:Gonglin Li、Mohuizi Liu、Sijia Zou、Xiaoming Feng、Lili Lin
DOI:10.1021/acs.orglett.0c03305
日期:2020.11.6
A unique chiral amine organocatalyst with a bispidine structure was found to be efficient for the diastereo- and enantioselective Mannich reaction of isatin ketimines with ketones. A series of 3-substituted 3-amino-2-oxindoles bearing vicinal tertiary and quaternary chiral stereogenic centers were obtained in excellent yields with excellent dr and ee values. The gram-scale synthesis and transformation
catalyzed by chiral Cinchona alkaloid based squaramide containing H-bond donor catalysts, wherein, the reaction of 1,3-diketones with isatin (N-Boc) ketimines led to the formation of 3-aminooxindole derivatives. These derivatives were obtained in high yields with excellent enantioselectivities under mild conditions using 3 mol% of the catalyst. This protocol provides valuable and easy access to chiral 3-substituted
A highly stereoselective synthesis of functionalized 3,3'-pyrrolidinyl-dispirooxindole derivatives with three stereogenic centers, including two contiguous spiro-stereocenters, has been achieved through an organocatalytic Mannich/Boc-deprotection /aza-Michael sequence. Employing the commercially available (DHQD)2PHAL...