Volume 2021, Issue 37 p. 5193-5201
Full Paper

Stereoselective Mannich Reaction of α-Acetoxy-β-keto Esters with Isatin Imine: An Efficient Access to Vicinal Tetra-Substituted Stereocenters

Dr. Jasneet Kaur

Dr. Jasneet Kaur

Department of Chemistry Khalsa College, Amritsar, 143001 India

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Banni Preet Kaur

Banni Preet Kaur

Department of Chemistry, U.G.C. Centre of Advance Studies in Chemistry, Guru Nanak Dev University, Amritsar, 143005 India

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Dr. Nasarul Islam

Dr. Nasarul Islam

Department of Chemistry, Govt. Degree College, Bandipora, 193502 India

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Pankaj Chauhan

Pankaj Chauhan

Department of Chemistry, Indian Institute of Technology Jammu, Jagti PO Nagrota, NH-44, Jammu, 181 221 India

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Dr. Swapandeep Singh Chimni

Corresponding Author

Dr. Swapandeep Singh Chimni

Department of Chemistry, U.G.C. Centre of Advance Studies in Chemistry, Guru Nanak Dev University, Amritsar, 143005 India

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First published: 10 September 2021

Graphical Abstract

Synthesis of optically active 3-substituted-3-aminooxindoles containing vicinal quaternary stereogenic centers was achieved using a quinine thiourea organocatalyst. α-Acetoxy-β-keto esters have been introduced as nucleophiles to undergo Mannich reaction with isatin imines for asymmetric organocatalysis.

Abstract

A highly diastereo- and enantioselective Mannich reaction of α-acetoxy-β-keto esters with isatin imine was developed. The quinine thiourea organocatalyst smoothly promoted the asymmetric Mannich reaction to furnish various 3-substituted-3-aminooxindole derivatives bearing two adjacent tetra-substituted stereocenters in up to 93 % yield, up to 98 % ee with >20 : 1 dr. The transition state structure and absolute configuration of the obtained product were predicted using DFT calculations, and results from single crystal X-ray analysis are in agreement with the DFT studies.

Conflict of interest

The authors declare no conflict of interest.