Chiral Squaramide-Catalyzed Enantioselective Decarboxylative Addition of β-Keto Acids to Isatin Imines
作者:Jasneet Kaur、Anita Kumari、Vimal K. Bhardwaj、Swapandeep Singh Chimni
DOI:10.1002/adsc.201700011
日期:2017.5.17
An efficient chiral squaramide‐catalyzed enantioselective decarboxylative addition reaction of β‐keto acids to isatinimines has been developed. The reaction proceeds smoothly using 20 mol% of organocatalyst to afford the chiral 3‐aminooxindoles in high yield and excellent enantioselectivities.
A highly enantioselective addition of diphenylphosphite to ketimines derived from isatins has been developed employing bifunctional thiourea-tertiary amine organocatalysts. A variety of isatins derived ketimines react well with diphenylphosphite in the presence of Cinchona-derived thiourea (epiCDT) to provide biologically important chiral 3-substituted 3-amino-2-oxindoles (3a–l) in good yield (up
A highlyenantioselective Morita–Baylis–Hillman reaction of maleimides with isatin derived ketimines has been developed to obtain enantiomerically enriched 3-substituted-3-aminooxindoles using β-isocupreidine as an organocatalyst. Maleimide acting as a nucleophile provides products with up to 99% ee.
An organocatalytic asymmetric aza-Henry reaction of ketimines derived from isatins with nitroalkanes has been achieved using Cinchona alkaloid organocatalysts. This method works efficiently with several ketimines to produce a good (up to 82%) yield of the corresponding 3-substituted 3-amino-2-oxindoles with a good (up to 89%) enantiomeric excess.